Merge changes from release branch into trunk.

doc/ZEO/ClientStorage.txt

@@ -23,7 +23,9 @@ ClientStorage
       - a sequence of the previous two
 
     If a sequence of addresses is specified, the client will use the
-    first server from the list that it can connect to.
+    first server from the list that it can connect to, subject to the
+    constraints imposed by the optional read_only and
+    read_only_fallback keyword arguments.
 
     The ClientStorage constructor provides a number of additional
     options (arguments). The full list of arguments is:
@@ -36,7 +38,7 @@ ClientStorage
       default name for both the server and client is '1'.
 
     cache_size -- The number of bytes to allow for the client cache.
-      The default is 20,000,000.  A large cache can significantly
+      The default is 20MB.  A large cache can significantly
       increase the performance of a ZEO system.  For applications that
       have a large database, the default size may be too small.
 
@@ -93,3 +95,8 @@ ClientStorage
 
       Each storage served by a ZEO server can be configured as either
       read-write or read-only.
+
+    read_only_fallback -- A flag indicating whether a read-only
+      remote storage should be acceptable as a fallback when no
+      writable storages are available.  Defaults to false.  At most
+      one of read_only and read_only_fallback should be true.

doc/ZEO/NonZopeREADME.txt

@@ -20,7 +20,7 @@ Zope Enterprize Objects
       python test.py -v
 
     Run the script with the -h option for a full list of options.  The
-    ZEO 2.0a1 release contains 87 unit tests on Unix.
+    ZEO 2.0b2 release contains 122 unit tests on Unix.
 
   Starting (and configuring) the ZEO Server
 
@@ -75,6 +75,6 @@ Zope Enterprize Objects
 
   Dependencies on other modules
 
-    ZEO depends on other modules that are distributed with
-    StandaloneZODB and with Zope.  You can download StandaloneZODB
-    from http://www.zope.org/Products/StandaloneZODB.
+    ZEO depends on other modules that are distributed with ZODB3 and
+    with Zope.  You can download ZODB3 from
+    http://www.zope.org/Products/StandaloneZODB.

doc/ZEO/ZopeREADME.txt

-Zope Enterprise Objects
+Zope Enterprise Objects (ZEO)
 
   Installation
 
@@ -19,7 +19,7 @@ Zope Enterprise Objects
       python test.py -v
 
     Run the script with the -h option for a full list of options.  The
-    ZEO 2.0a1 release contains 87 unit tests on Unix.
+    ZEO 2.0b2 release contains 122 unit tests on Unix.
 
   Starting (and configuring) the ZEO Server
 
@@ -93,4 +93,4 @@ Zope Enterprise Objects
     once with the environment variable FORCE_PRODUCT_LOAD set.
 
     The interaction between ZEO and Zope product installation is
-    unfortunate.  In the future, this interaction will be removed by 
+    unfortunate.

doc/guide/TODO

-Update text to use BTrees, not BTree
 Write section on __setstate__
-Connection.sync seems to work now; note this
 Continue working on it
 Suppress the full GFDL text in the PDF/PS versions
 

doc/guide/links.tex

@@ -17,6 +17,14 @@ how it's actually implemented.  A definitive reference, and highly recommended.
 \\
 \url{http://www.python.org/workshops/2000-01/proceedings/papers/fulton/zodb3.html}
 
+Persistent Programing with ZODB, by Jeremy Hylton and Barry Warsaw:
+\\
+Slides for a tutorial presented at the 10th Python conference.  Covers
+much of the same ground as this guide, with more details in some areas
+and less in others.
+\\
+\url{http://www.zope.org/Members/bwarsaw/ipc10-slides}
+
 Download link for ZEO: \\
 \url{http://www.zope.org/Products/ZEO/}
 

doc/guide/modules.tex

@@ -2,13 +2,12 @@
 % Related Modules
 %    PersistentMapping
 %    PersistentList
-%    BTree
-%    Catalog
+%    BTrees
 
 \section{Related Modules}
 
 The ZODB package includes a number of related modules that provide
-useful data types such as BTrees or full-text indexes.
+useful data types such as BTrees.
 
 \subsection{\module{ZODB.PersistentMapping}}
 
@@ -40,51 +39,92 @@ value for \var{initlist}, a regular Python list is used.
 Python lists do.
 
 
-\subsection{B-tree Modules}
-
-%here's one: how does one implement searching? i would have expected the
-%btree objects to have ``find key nearest to this'' and ``next'' methods,
-%(like bsddb's set_location)...
-%
-%  -- erno
+\subsection{BTrees Package}
 
 When programming with the ZODB, Python dictionaries aren't always what
 you need.  The most important case is where you want to store a very
 large mapping.  When a Python dictionary is accessed in a ZODB, the
 whole dictionary has to be unpickled and brought into memory.  If
 you're storing something very large, such as a 100,000-entry user
-database, unpickling such a large object will be slow.  B-trees are a
+database, unpickling such a large object will be slow.  BTrees are a
 balanced tree data structure that behave like a mapping but distribute
-keys throughout a number of tree nodes.  Nodes are then only unpickled
-and brought into memory as they're accessed, so the entire tree
-doesn't have to occupy memory (unless you really are touching every
-single key).
-
-There are four different BTree modules provided.  One of them, the
-\module{BTree} module, provides the most general data type; the keys
-and values in the B-tree can be any Python object.  Some specialized B-tree
-modules require that the keys, and perhaps even the values, to be of a
-certain type, and provide faster performance because of this limitation.
-
-\begin{itemize}
-\item[ \module{IOBTree} ] requires the keys to be integers.
-The module name reminds you of this; the \module{IOBTree} module
-maps Integers to Objects.
-
-\item[ \module{OIBTree} ] requires the values to be integers,
-mapping Objects to Integers.
-
-\item[ \module{IIBTree} ] is strictest, requiring that both keys and values must be integers.
-
-\end{itemize}
-
-To use a B-tree, simply import the desired module and call the
-constructor, always named \function{BTree()}, to get a B-tree
-instance, and then use it like any other mapping:
+keys throughout a number of tree nodes.  The nodes are stored in
+sorted order.  Nodes are then only unpickled and brought into memory
+as they're accessed, so the entire tree doesn't have to occupy memory
+(unless you really are touching every single key).
+
+The BTrees package provides a large collection of related data
+structures.  There are variants of the data structures specialized to
+handle integer values, which are faster and use less memory.  There
+are four modules that handle the different variants.  The first two
+letters of the module name specify the types of the keys and values in
+mappings -- O for any object and I for integer.  The
+\module{BTrees.IOBTree} module provides a mapping that accepts integer
+keys and arbitrary objects as values.
+
+The four data structures provide by each module are a btree, a bucket,
+a tree set, and a set.  The btree and bucket types are mappings and
+support all the usual mapping methods, e.g. \function{update()} and
+\function{keys()}.  The tree set and set types are similar to mappings
+but they have no values; they support the methods that make sense for
+a mapping with no keys, e.g. \function{keys()} but not
+\function{items()}.  The bucket and set types are the individual
+building blocks for btrees and tree sets, respectively.  A bucket or
+set can be used when you are sure that it will have few elements.  If
+the data structure will grow large, you should use a btree or tree
+set.
+
+The four modules are named \module{OOBTree}, \module{IOBTree},
+\module{OIBTree}, and \module{IIBTree}.  The two letter prefixes are
+repeated in the data types names.  The \module{BTrees.OOBTree} module
+defines the following types: \class{OOBTree}, \class{OOBucket},
+\class{OOSet}, and \class{OOTreeSet}.
+
+The \function{keys()}, \function{values()}, and \function{items()}
+methods do not materialize a list with all of the data.  Instead, they
+return lazy sequences that fetch data from the BTree as needed.  They
+also support optional arguments to specify the minium and maximum
+values to return.
+
+A BTree object supports all the methods you would expect of a mapping
+with a few extensions that exploit the fact that the keys are sorted.
+The example below demonstrates how some of the methods work.  The
+extra methods re \function{minKey()} and \function{maxKey()}, which
+find the minimum and maximum key value subject to an optional bound
+argument, and \function{byValue()}, which returns value, key pairs
+in reversed sorted order subject to an optional minimum bound argument.
 
 \begin{verbatim}
-import IIBTree
-iimap = IIBTree.BTree()
-iimap[1972] = 27
+>>> from BTrees.OOBTree import OOBTree
+>>> t = OOBTree()
+>>> t.update({ 1: "red", 2: "green", 3: "blue", 4: "spades" })
+>>> len(t)
+4
+>>> t[2]
+'green'
+>>> t.keys()
+<OOBTreeItems object at 0x40269098>
+>>> [k for k in t.keys()] # use a listcomp to get a printable sequence
+[1, 2, 3, 4]
+>>> [k for k in t.values()]
+['red', 'green', 'blue', 'spades']
+>>> [k for k in t.values(1, 2)]
+['red', 'green']
+>>> [k for k in t.values(2)]
+['green', 'blue', 'spades']
+>>> t.byValue("glue") # all values > "glue"
+[('spades', 4), ('red', 1), ('green', 2)]
+>>> t.minKey(1.5)
+2
 \end{verbatim}
 
+Each of the modules also defines some functions that operate on
+BTrees -- \function{difference()}, \function{union()}, and
+\function{difference()}.  The \function{difference()} function returns
+a bucket, while the other two methods return a set.
+If the keys are integers, then the module also defines
+\function{multiunion()}.  If the values are integers, then the module
+also defines \function{weightedIntersection()} and
+\function{weighterUnion()}.  The function doc strings describe each
+function briefly.
+

doc/guide/transactions.tex

@@ -35,7 +35,7 @@ or \method{abort()} method of the \class{Transaction} object.
 
 \begin{verbatim}
 # Commit a subtransaction
-get_transaction().commit(1)	
+get_transaction().commit(1)     
 
 # Abort a subtransaction
 get_transaction().abort(1)   
@@ -103,6 +103,16 @@ transaction''.  Usually this will happen because later transactions
 modified the objects affected by the transaction you're trying to
 undo.
 
+After you call \method{undo()} you must commit the transaction for the
+undo to actually be applied.
+\footnote{There are actually two different ways a storage can
+implement the undo feature.  Most of the storages that ship with ZODB
+use the transactional form of undo described in the main text.  Some
+storages may use a non-transactional undo makes changes visible
+immediately.}  There is one glitch in the undo process.  The thread
+that calls undo may not see the changes to the object until it calls
+\method{Connection.sync()} or commits another transaction.
+
 \subsection{Versions}
 
 While many subtransactions can be contained within a single regular
@@ -161,6 +171,3 @@ The \class{Storage} and \class{DB} instances can be shared among
 several threads, as long as individual \class{Connection} instances
 are created for each thread.  
 
-XXX I can't think of anything else to say about multithreaded ZODB
-programs.  Suggestions?  An example program?
-

doc/guide/zeo.tex

@@ -18,22 +18,21 @@ them in a distributed fashion without Zope ever entering the picture.
 The combination of ZEO and ZODB is essentially a Python-specific
 object database.
 
-ZEO consists of about 1400 lines of Python code.  The code is
-relatively small because it contains only code for a TCP/IP server,
-and for a new type of Storage, \class{ClientStorage}.
-\class{ClientStorage} doesn't use disk files at all; it simply
-makes remote procedure calls to the server, which then passes them on
-a regular \class{Storage} class such as \class{FileStorage}.  The
-following diagram lays out the system:
+ZEO consists of about 6000 lines of Python code, excluding tests.  The
+code is relatively small because it contains only code for a TCP/IP
+server, and for a new type of Storage, \class{ClientStorage}.
+\class{ClientStorage} simply makes remote procedure calls to the
+server, which then passes them on a regular \class{Storage} class such
+as \class{FileStorage}.  The following diagram lays out the system:
 
 XXX insert diagram here later
 
 Any number of processes can create a \class{ClientStorage}
 instance, and any number of threads in each process can be using that
 instance.  \class{ClientStorage} aggressively caches objects
-locally, so in order to avoid using stale data, the ZEO server sends
-an invalidate message to all the connected \class{ClientStorage}
-instances on every write operation.  The invalidate message contains
+locally, so in order to avoid using stale data.  The ZEO server sends
+an invalidation message to all the connected \class{ClientStorage}
+instances on every write operation.  The invalidation message contains
 the object ID for each object that's been modified, letting the
 \class{ClientStorage} instances delete the old data for the
 given object from their caches.
@@ -46,7 +45,9 @@ writes, and ZEO is therefore better suited for read-intensive
 applications.  If every \class{ClientStorage} is writing to the
 database all the time, this will result in a storm of invalidate
 messages being sent, and this might take up more processing time than
-the actual database operations themselves.
+the actual database operations themselves.\footnote{These messages are
+small and sent in batches, so there would need to be a lot of writes
+before it became a problem.}
 
 On the other hand, for applications that have few writes in comparison
 to the number of read accesses, this aggressive caching can be a major
@@ -69,36 +70,17 @@ configure and run a ZEO Storage Server on a machine.
 
 \subsubsection{Requirements}
 
-To run a ZEO server, you'll need Python 1.5.2 or 2.0, and the ZODB
-packages from \url{http://www.amk.ca/files/zodb/}
-have to be installed.  
-
-\emph{Note for Python 1.5.2 users}: ZEO requires updated versions
-of the \module{asyncore.py} and \module{asynchat.py} modules that are
-included in 1.5.2's standard library.  Current versions of the ZODB
-distribution install private versions of these modules, so you
-shouldn't need to grab updated versions yourself.  (The symptom of
-this problem is a traceback on attempting to run a ZEO client program:
-the traceback is ``TypeError: too many arguments; expected 2, got 3''
-around line 100 of \file{smac.py}.
-
-\subsubsection{Installation}
-
-Installing the ZEO package is easy.  Just run \code{python setup.py
-install}.  This will install the ZEO/ package into your Python
-installation, and copy various files into their proper locations:
-\file{zeo.conf} will be put into \file{/usr/local/etc/}, a \file{zeo} startup
-script will be put in \file{/etc/rc.d/init.d/}, and the \file{zeod}
-daemon program will be placed in \file{/usr/local/bin}.
-
-\subsection{Configuring and Running a ZEO Server}
-
-Edit \code{/usr/local/etc/zeo.conf} appropriately for your desired
-setup.  This configuration file controls the port on which ZEO will
-listen for connections, the user and group IDs under which the server
-will be executed, and the location of the concrete \class{Storage}
-object that will be made network-accessible.
- 
+The ZEO server software is included in ZODB3.  As with the rest of
+ZODB3, you'll need Python 2.1 or higher.
+
+\subsubsection{Running a server}
+
+The start.py script in the ZEO directory can be used to start a
+server.  Run it with the -h option to see the various values.  If
+you're just experimenting, a good choise is to use 
+\code{python ZEO/start.py -D -U /tmp/zeosocket} to run ZEO in
+debug mode and with a Unix domain socket.
+
 \subsection{Testing the ZEO Installation}
 
 Once a ZEO server is up and running, using it is just like using ZODB
@@ -137,15 +119,15 @@ If this code runs properly, then your ZEO server is working correctly.
 
 \subsection{ZEO Programming Notes}
 
-XXX The Connection.sync() method and its necessity (if it works at all!) 
-
-% That doesn't work.  I tested it.  sync() doesn't seem to get into
-% the asyncore loop.  One of us should probably look into adding an
-% API for this when we have some free time.  It would be a nice
-% small project that would get into ZODB's guts.
-
-
-
+ZEO is written using \module{asyncore}, from the Python standard
+library.  It assumes that some part of the user application is running
+an \module{asyncore} mainloop.  For example, Zope run the loop in a
+separate thread and ZEO uses that.  If your application does not have
+a mainloop, ZEO will not process incoming invalidation messages until
+you make some call into ZEO.  The \method{Connection.sync} method can
+be used to process pending invalidation messages.  You can call it
+when you want to make sure the \class{Connection} has the most recent
+version of every object, but you don't have any other work for ZEO to do.
 
 \subsection{Sample Application: chatter.py}
 
@@ -174,7 +156,7 @@ class ChatSession(Persistent):
     def __init__(self, name):
         self.name = name
         # Internal attribute: _messages holds all the chat messages.        
-        self._messages = BTree.BTree()        
+        self._messages = BTrees.OOBTree.OOBTree()        
 \end{verbatim}
 
 \method{add_message()} has to add a message to the

doc/guide/zodb.tex

 \documentclass{howto}
 
 \title{ZODB/ZEO Programming Guide}
-\release{0.03}
+\release{0.04}
 \date{\today}
 
 \author{A.M.\ Kuchling}

doc/guide/zodb/about.html

@@ -6,19 +6,20 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="previous" HREF="node41.html">
+<LINK REL="previous" HREF="node39.html">
 <LINK REL="up" HREF="zodb.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
 <tr>
-<td><A HREF="node53.html"><img src="/python/writing/icons/previous.gif"
+<td><A HREF="node51.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
 <td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
@@ -38,7 +39,7 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node53.html">ADDENDUM: How to use</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node51.html">ADDENDUM: How to use</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
 <br><hr>
 </DIV>
@@ -48,7 +49,7 @@
 About this document ...</A>
 </H1>
  <strong>ZODB/ZEO Programming Guide</strong>,
-February 8, 2002, Release 0.03
+October 4, 2002, Release 0.04
 <p> This document was generated using the <a
     href="http://saftsack.fs.uni-bayreuth.de/~latex2ht/">
     <strong>LaTeX</strong>2<tt>HTML</tt></a> translator.
@@ -78,7 +79,7 @@ February 8, 2002, Release 0.03
 <p><hr>
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
 <tr>
-<td><A HREF="node53.html"><img src="/python/writing/icons/previous.gif"
+<td><A HREF="node51.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
 <td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
@@ -98,10 +99,10 @@ February 8, 2002, Release 0.03
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node53.html">ADDENDUM: How to use</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node51.html">ADDENDUM: How to use</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/contents.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="zodb.html">
 <LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node2.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -66,45 +67,44 @@ Contents</A>
 <LI><A href="node13.html">2.3 Opening a ZODB</a>
 <LI><A href="node14.html">2.4 Writing a Persistent Class</a>
 <LI><A href="node15.html">2.5 Rules for Writing Persistent Classes</a>
-<LI><A href="node20.html">2.6 Writing Persistent Classes</a>
+<LI><A href="node19.html">2.6 Writing Persistent Classes</a>
 </ul>
 <LI><A href="zeo.html">3 ZEO</a>
 <UL>
-<LI><A href="node23.html">3.1 How ZEO Works</a>
-<LI><A href="node24.html">3.2 Installing ZEO</a>
-<LI><A href="node27.html">3.3 Configuring and Running a ZEO Server</a>
-<LI><A href="node28.html">3.4 Testing the ZEO Installation</a>
-<LI><A href="node29.html">3.5 ZEO Programming Notes</a>
-<LI><A href="node30.html">3.6 Sample Application: chatter.py</a>
+<LI><A href="node22.html">3.1 How ZEO Works</a>
+<LI><A href="node23.html">3.2 Installing ZEO</a>
+<LI><A href="node26.html">3.3 Testing the ZEO Installation</a>
+<LI><A href="node27.html">3.4 ZEO Programming Notes</a>
+<LI><A href="node28.html">3.5 Sample Application: chatter.py</a>
 </ul>
-<LI><A href="node31.html">4 Transactions and Versioning</a>
+<LI><A href="node29.html">4 Transactions and Versioning</a>
 <UL>
-<LI><A href="node32.html">4.1 Subtransactions</a>
-<LI><A href="node33.html">4.2 Undoing Changes</a>
-<LI><A href="node34.html">4.3 Versions</a>
-<LI><A href="node35.html">4.4 Multithreaded ZODB Programs</a>
+<LI><A href="node30.html">4.1 Subtransactions</a>
+<LI><A href="node31.html">4.2 Undoing Changes</a>
+<LI><A href="node32.html">4.3 Versions</a>
+<LI><A href="node33.html">4.4 Multithreaded ZODB Programs</a>
 </ul>
-<LI><A href="node36.html">5 Related Modules</a>
+<LI><A href="node34.html">5 Related Modules</a>
 <UL>
-<LI><A href="node37.html">5.1 <tt class="module">ZODB.PersistentMapping</tt></a>
-<LI><A href="node38.html">5.2 <tt class="module">ZODB.PersistentList</tt></a>
-<LI><A href="node39.html">5.3 B-tree Modules</a>
+<LI><A href="node35.html">5.1 <tt class="module">ZODB.PersistentMapping</tt></a>
+<LI><A href="node36.html">5.2 <tt class="module">ZODB.PersistentList</tt></a>
+<LI><A href="node37.html">5.3 BTrees Package</a>
 </ul>
-<LI><A href="node40.html">A. Resources</a>
-<LI><A href="node41.html">B. GNU Free Documentation License</a>
+<LI><A href="node38.html">A. Resources</a>
+<LI><A href="node39.html">B. GNU Free Documentation License</a>
 <UL>
-<LI><A href="node42.html">Preamble</a>
-<LI><A href="node43.html">B..1 Applicability and Definitions</a>
-<LI><A href="node44.html">B..2 Verbatim Copying</a>
-<LI><A href="node45.html">B..3 Copying in Quantity</a>
-<LI><A href="node46.html">B..4 Modifications</a>
-<LI><A href="node47.html">B..5 Combining Documents</a>
-<LI><A href="node48.html">B..6 Collections of Documents</a>
-<LI><A href="node49.html">B..7 Aggregation With Independent Works</a>
-<LI><A href="node50.html">B..8 Translation</a>
-<LI><A href="node51.html">B..9 Termination</a>
-<LI><A href="node52.html">B..10 Future Revisions of This Licence</a>
-<LI><A href="node53.html">ADDENDUM: How to use this License for your documents</a>
+<LI><A href="node40.html">Preamble</a>
+<LI><A href="node41.html">B..1 Applicability and Definitions</a>
+<LI><A href="node42.html">B..2 Verbatim Copying</a>
+<LI><A href="node43.html">B..3 Copying in Quantity</a>
+<LI><A href="node44.html">B..4 Modifications</a>
+<LI><A href="node45.html">B..5 Combining Documents</a>
+<LI><A href="node46.html">B..6 Collections of Documents</a>
+<LI><A href="node47.html">B..7 Aggregation With Independent Works</a>
+<LI><A href="node48.html">B..8 Translation</a>
+<LI><A href="node49.html">B..9 Termination</a>
+<LI><A href="node50.html">B..10 Future Revisions of This Licence</a>
+<LI><A href="node51.html">ADDENDUM: How to use this License for your documents</a>
 </ul>
 <LI><A href="about.html">About this document ...</a>
 </ul>
@@ -147,7 +147,7 @@ Contents</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node2.html">1 Introduction</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/images.tex

@@ -5,7 +5,7 @@
 
 
 \title{ZODB/ZEO Programming Guide}
-\release{0.03}
+\release{0.04}
 \date{\today}
 
 \author{A.M.\ Kuchling}\authoraddress{akuchlin@mems-exchange.org}
@@ -150,7 +150,6 @@
 \stepcounter{subsubsection}
 \stepcounter{subsubsection}
 \stepcounter{subsubsection}
-\stepcounter{subsubsection}
 \stepcounter{subsection}
 \stepcounter{subsubsection}
 \stepcounter{section}
@@ -161,7 +160,6 @@
 \stepcounter{subsection}
 \stepcounter{subsection}
 \stepcounter{subsection}
-\stepcounter{subsection}
 \stepcounter{section}
 \stepcounter{subsection}
 \stepcounter{subsection}
@@ -175,7 +173,7 @@
 \stepcounter{section}
 \stepcounter{section}
 {\newpage\clearpage
-\lthtmlinlinemathA{tex2html_wrap_inline847}%
+\lthtmlinlinemathA{tex2html_wrap_inline807}%
 $\copyright$%
 \lthtmlinlinemathZ
 \lthtmlcheckvsize\clearpage}

doc/guide/zodb/index.html

@@ -6,12 +6,13 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" href="contents.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -47,8 +48,8 @@
 <h1>ZODB/ZEO Programming Guide</h1>
 <p><b><font size="+2">A.M. Kuchling</font></b></p>
 <p>akuchlin@mems-exchange.org</p>
-<p><strong>Release 0.03</strong><br>
-<strong>February 8, 2002</strong></p>
+<p><strong>Release 0.04</strong><br>
+<strong>October 4, 2002</strong></p>
 <p>
 </center>
 </div>
@@ -81,55 +82,53 @@
 <UL>
 <LI><A href="node16.html">2.5.1 Modifying Mutable Objects</a>
 <LI><A href="node17.html">2.5.2 Some Special Methods Don't Work</a>
-<LI><A href="node18.html">2.5.3 Fixing <tt class="function">isinstance</tt> and <tt class="function">issubclass</tt></a>
-<LI><A href="node19.html">2.5.4 <tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, and <tt class="method">__setattr__</tt></a>
+<LI><A href="node18.html">2.5.3 <tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, and <tt class="method">__setattr__</tt></a>
 </ul>
-<LI><A href="node20.html">2.6 Writing Persistent Classes</a>
+<LI><A href="node19.html">2.6 Writing Persistent Classes</a>
 <UL>
-<LI><A href="node21.html">2.6.1 Changing Instance Attributes</a>
+<LI><A href="node20.html">2.6.1 Changing Instance Attributes</a>
 </ul>
 </ul>
 <LI><A href="zeo.html">3 ZEO</a>
 <UL>
-<LI><A href="node23.html">3.1 How ZEO Works</a>
-<LI><A href="node24.html">3.2 Installing ZEO</a>
+<LI><A href="node22.html">3.1 How ZEO Works</a>
+<LI><A href="node23.html">3.2 Installing ZEO</a>
 <UL>
-<LI><A href="node25.html">3.2.1 Requirements</a>
-<LI><A href="node26.html">3.2.2 Installation</a>
+<LI><A href="node24.html">3.2.1 Requirements</a>
+<LI><A href="node25.html">3.2.2 Running a server</a>
 </ul>
-<LI><A href="node27.html">3.3 Configuring and Running a ZEO Server</a>
-<LI><A href="node28.html">3.4 Testing the ZEO Installation</a>
-<LI><A href="node29.html">3.5 ZEO Programming Notes</a>
-<LI><A href="node30.html">3.6 Sample Application: chatter.py</a>
+<LI><A href="node26.html">3.3 Testing the ZEO Installation</a>
+<LI><A href="node27.html">3.4 ZEO Programming Notes</a>
+<LI><A href="node28.html">3.5 Sample Application: chatter.py</a>
 </ul>
-<LI><A href="node31.html">4 Transactions and Versioning</a>
+<LI><A href="node29.html">4 Transactions and Versioning</a>
 <UL>
-<LI><A href="node32.html">4.1 Subtransactions</a>
-<LI><A href="node33.html">4.2 Undoing Changes</a>
-<LI><A href="node34.html">4.3 Versions</a>
-<LI><A href="node35.html">4.4 Multithreaded ZODB Programs</a>
+<LI><A href="node30.html">4.1 Subtransactions</a>
+<LI><A href="node31.html">4.2 Undoing Changes</a>
+<LI><A href="node32.html">4.3 Versions</a>
+<LI><A href="node33.html">4.4 Multithreaded ZODB Programs</a>
 </ul>
-<LI><A href="node36.html">5 Related Modules</a>
+<LI><A href="node34.html">5 Related Modules</a>
 <UL>
-<LI><A href="node37.html">5.1 <tt class="module">ZODB.PersistentMapping</tt></a>
-<LI><A href="node38.html">5.2 <tt class="module">ZODB.PersistentList</tt></a>
-<LI><A href="node39.html">5.3 B-tree Modules</a>
+<LI><A href="node35.html">5.1 <tt class="module">ZODB.PersistentMapping</tt></a>
+<LI><A href="node36.html">5.2 <tt class="module">ZODB.PersistentList</tt></a>
+<LI><A href="node37.html">5.3 BTrees Package</a>
 </ul>
-<LI><A href="node40.html">A. Resources</a>
-<LI><A href="node41.html">B. GNU Free Documentation License</a>
+<LI><A href="node38.html">A. Resources</a>
+<LI><A href="node39.html">B. GNU Free Documentation License</a>
 <UL>
-<LI><A href="node42.html">Preamble</a>
-<LI><A href="node43.html">B..1 Applicability and Definitions</a>
-<LI><A href="node44.html">B..2 Verbatim Copying</a>
-<LI><A href="node45.html">B..3 Copying in Quantity</a>
-<LI><A href="node46.html">B..4 Modifications</a>
-<LI><A href="node47.html">B..5 Combining Documents</a>
-<LI><A href="node48.html">B..6 Collections of Documents</a>
-<LI><A href="node49.html">B..7 Aggregation With Independent Works</a>
-<LI><A href="node50.html">B..8 Translation</a>
-<LI><A href="node51.html">B..9 Termination</a>
-<LI><A href="node52.html">B..10 Future Revisions of This Licence</a>
-<LI><A href="node53.html">ADDENDUM: How to use this License for your documents</a>
+<LI><A href="node40.html">Preamble</a>
+<LI><A href="node41.html">B..1 Applicability and Definitions</a>
+<LI><A href="node42.html">B..2 Verbatim Copying</a>
+<LI><A href="node43.html">B..3 Copying in Quantity</a>
+<LI><A href="node44.html">B..4 Modifications</a>
+<LI><A href="node45.html">B..5 Combining Documents</a>
+<LI><A href="node46.html">B..6 Collections of Documents</a>
+<LI><A href="node47.html">B..7 Aggregation With Independent Works</a>
+<LI><A href="node48.html">B..8 Translation</a>
+<LI><A href="node49.html">B..9 Termination</a>
+<LI><A href="node50.html">B..10 Future Revisions of This Licence</a>
+<LI><A href="node51.html">ADDENDUM: How to use this License for your documents</a>
 </ul>
 <LI><A href="about.html">About this document ...</a>
 </ul>
@@ -161,7 +160,7 @@
 </tr></table>
 <b class="navlabel">Next:</b> <a class="sectref" href="contents.html">Contents</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node10.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node9.html">
 <LINK REL="up" HREF="node9.html">
 <LINK REL="next" HREF="node11.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -52,36 +53,15 @@
 </H3>
 
 <P>
-You'll need Python, of course; version 1.5.2 works with some fixes,
-and it also works with Python 2.0, which is what I primarily use.
-
-<P>
-The code is packaged using Distutils, the new distribution tools for
-Python introduced in Python 2.0.  If you're using 1.5.2, first you'll
-have to get the latest Distutils release from the Distutils SIG page
-at <a class="url" href="http://www.python.org/sigs/distutils-sig/download.html">http://www.python.org/sigs/distutils-sig/download.html</a> and
-install it.  This is simply a matter of untarring or unzipping the
+You will need Python 2.1 or higher.  The code is packaged using
+Distutils.  So it is simply a matter of untarring or unzipping the
 release package, and then running <code>python setup.py install</code>.
 
-<P>
-If you're using 1.5.2 and have installed previous versions of the
-Distutils, be sure to get the very latest version, since developing
-the ZODB distribution turned up some bugs along the way.  If you
-encounter problems compiling <span class="file">ZODB/TimeStamp.c</span> or your compiler reports
-an error like ``Can't create build/temp.linux2/ExtensionClass.o: No
-such file or directory'', you need an updated version.  Old versions of
-Distutils have two bugs which affect the setup scripts.  First, for a
-long time the <code>define_macros</code> keyword in setup.py files didn't work due
-to a Distutils bug, so I hacked TimeStamp.c in earlier releases.  The
-Distutils have since been fixed, and the hack became unnecessary, so I
-removed it.  Second, the code that creates directories tries to be
-smart and caches them to save time by not trying to create a directory
-twice, but this code was broken in old versions.
-
 <P>
 You'll need a C compiler to build the packages, because there are
 various C extension modules.  At the moment no one is making Windows
-binaries available, so you'll need a Windows development environment to use the 
+binaries available, so you'll need a Windows development environment
+to build ZODB.
 
 <P>
 
@@ -113,7 +93,7 @@ binaries available, so you'll need a Windows development environment to use the
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node9.html">2.1 Installing ZODB</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node11.html">2.1.2 Installing the Packages</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node11.html

@@ -6,14 +6,15 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="previous" HREF="node10.html">
 <LINK REL="up" HREF="node9.html">
 <LINK REL="next" HREF="node12.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -52,38 +53,9 @@
 
 <P>
 Download the ZODB tarball containing all the packages for both ZODB
-and ZEO from <a class="url" href="http://www.amk.ca/files/zodb/">http://www.amk.ca/files/zodb/</a>.
-
-<P>
-To build the packages, you must go into the individual directories and
-build and install them one by one.  They should be built and installed
-in this order:
-
-<P>
-
-<OL>
-<LI><code>zodb-basic</code>
-</LI>
-<LI>ExtensionClass
-</LI>
-<LI>ZODB
-</LI>
-<LI><code>BTree</code> and <code>BTrees</code>
-</LI>
-<LI>ZEO
-</LI>
-</OL>
-
-<P>
-In particular, you must install ExtensionClass before building the
-ZODB package; otherwise, the compilation in the ZODB package will die
-complaining that it can't find ExtensionClass.h.  You can manually
-hack the #include path to make it work without installing
-ExtensionClass first, but that's a bit hackish.
-
-<P>
-If you encounter any problems, please let me know at
-<span class="email">akuchlin@mems-exchange.org</span>.
+and ZEO from <a class="url" href="http://www.zope.org/Products/StandaloneZODB">http://www.zope.org/Products/StandaloneZODB</a>.  See
+the <span class="file">README.txt</span> file in the top level of the release directory
+for details on building, testing, and installing.
 
 <P>
 
@@ -115,7 +87,7 @@ If you encounter any problems, please let me know at
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node9.html">2.1 Installing ZODB</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node12.html">2.2 How ZODB Works</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node12.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node9.html">
 <LINK REL="up" HREF="node8.html">
 <LINK REL="next" HREF="node13.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -91,10 +92,16 @@ state.
 <DT>Consistency</DT>
 <DD>means that the data cannot be placed into a
 logically invalid state; sanity checks can be written and enforced.
-Usually this is done by defining a database schema, and requiring the
-data always matches the schema.  For example, this might enforce that
-the <code>order_number</code> attribute is always an integer, and not a
-string, tuple, or other object.
+Usually this is done by defining a database schema, and requiring
+the data always matches the schema.  There are two typical
+approaches to consistency.  One is to enforce rules about the types
+of objects and attribute; for example, enforce that the
+<code>order_number</code> attribute is always an integer, and not a
+string, tuple, or other object.  Another is to guarantee consistency
+across data structures; for example, that any object with an
+<code>order_number</code> attribute must also appear in the
+<code>orders_table</code> object.  In general, atomicity and isolation make
+it possible for applications to provide consistency.
 
 <P>
 </DD>
@@ -148,7 +155,7 @@ has no way of enforcing consistency with a schema.
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node13.html">2.3 Opening a ZODB</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node13.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node12.html">
 <LINK REL="up" HREF="node8.html">
 <LINK REL="next" HREF="node14.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -65,7 +66,7 @@ implement the <tt class="class">Storage</tt> interface.
  storing and retrieving objects from some form of long-term storage.
  A few different types of Storage have been written, such as
  <tt class="class">FileStorage</tt>, which uses regular disk files, and
- <tt class="class">BerkeleyStorage</tt>, which uses Sleepycat Software's BerkeleyDB
+ <tt class="class">bsddb3Storage</tt>, which uses Sleepycat Software's BerkeleyDB
  database.  You could write a new Storage that stored objects in a
  relational database or Metakit file, for example, if that would
  better suit your application.  Two example storages,
@@ -81,7 +82,7 @@ implement the <tt class="class">Storage</tt> interface.
 <P>
 </LI>
 <LI>Finally, the <tt class="class">Connection</tt> class caches objects, and moves
- them into and out of object storage.  A multi-threaded program can
+ them into and out of object storage.  A multi-threaded program should
  open a separate <tt class="class">Connection</tt> instance for each thread.
  Different threads can then modify objects and commit their
  modifications independently.
@@ -97,13 +98,13 @@ a <tt class="class">Connection</tt> from the <tt class="class">DB instance</tt>.
 code:
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
 from ZODB import FileStorage, DB
 
 storage = FileStorage.FileStorage('/tmp/test-filestorage.fs')
 db = DB(storage)
 conn = db.open()
-</pre></dl>
+</pre></div>
 
 <P>
 Note that you can use a completely different data storage mechanism by
@@ -141,7 +142,7 @@ you'll see how ZEO uses this flexibility to good effect.
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node14.html">2.4 Writing a Persistent</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node14.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node13.html">
 <LINK REL="up" HREF="node8.html">
 <LINK REL="next" HREF="node15.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -56,13 +57,13 @@ Making a Python class persistent is quite simple; it simply needs to
 subclass from the <tt class="class">Persistent</tt> class, as shown in this example:
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
 import ZODB
 from Persistence import Persistent
 
 class User(Persistent):
     pass
-</pre></dl>
+</pre></div>
 
 <P>
 The apparently unnecessary <code>import ZODB</code> statement is
@@ -70,6 +71,11 @@ needed for the following <code>from...import</code> statement to work
 correctly, since the ZODB code does some magical tricks with
 importing.
 
+<P>
+The <tt class="class">Persistent</tt> base class is an <tt class="module">ExtensionClass</tt>
+class.  As a result, it not compatible with new-style classes or types
+in Python 2.2 and up.
+
 <P>
 For simplicity, in the examples the <tt class="class">User</tt> class will
 simply be used as a holder for a bunch of attributes.  Normally the
@@ -96,7 +102,7 @@ that will contain all the <tt class="class">User</tt> objects.  (The
 <tt class="class">BTree</tt> module is also included as part of Zope.)
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
 dbroot = conn.root()
 
 # Ensure that a 'userdb' key is present 
@@ -106,7 +112,7 @@ if not dbroot.has_key('userdb'):
     dbroot['userdb'] = BTree.BTree()
 
 userdb = dbroot['userdb']
-</pre></dl>
+</pre></div>
 
 <P>
 Inserting a new user is simple: create the <tt class="class">User</tt> object, fill
@@ -114,7 +120,7 @@ it with data, insert it into the <tt class="class">BTree</tt> instance, and comm
 this transaction.
 
 <P>
-<dl><dd><pre class="verbatim"># Create new User instance
+<div class="verbatim"><pre># Create new User instance
 newuser = User() 
 
 # Add whatever attributes you want to track
@@ -127,7 +133,7 @@ userdb[newuser.id] = newuser
 
 # Commit the change
 get_transaction().commit()
-</pre></dl>
+</pre></div>
 
 <P>
 When you import the ZODB package, it adds a new function,
@@ -146,7 +152,7 @@ having transactional semantics for your program's variables, and you
 can experiment with transactions at the Python interpreter's prompt:
 
 <P>
-<dl><dd><pre class="verbatim">&gt;&gt;&gt; newuser
+<div class="verbatim"><pre>&gt;&gt;&gt; newuser
 &lt;User instance at 81b1f40&gt;
 &gt;&gt;&gt; newuser.first_name           # Print initial value
 'Andrew'         
@@ -156,7 +162,7 @@ can experiment with transactions at the Python interpreter's prompt:
 &gt;&gt;&gt; get_transaction().abort()    # Abort transaction
 &gt;&gt;&gt; newuser.first_name           # The value has changed back
 'Andrew'
-</pre></dl>
+</pre></div>
 
 <P>
 
@@ -188,7 +194,7 @@ can experiment with transactions at the Python interpreter's prompt:
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node15.html

@@ -6,15 +6,16 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node20.html">
+<LINK REL="next" HREF="node19.html">
 <LINK REL="previous" HREF="node14.html">
 <LINK REL="up" HREF="node8.html">
 <LINK REL="next" HREF="node16.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -81,13 +82,6 @@ defined on ExtensionClasses.  The most important ones are the
 arithmetic operations: <tt class="method">__radd__</tt>, <tt class="method">__rsub__</tt>, and so
 forth.
 
-<P>
-</LI>
-<LI>Python's built-in <tt class="function">isinstance()</tt> and <tt class="function">issubclass()</tt>
-functions don't work properly on ExtensionClasses.  Solution: use
-custom <tt class="function">isinstance()</tt> and <tt class="function">issubclass()</tt> functions
-that handle ExtensionClasses correctly.
-
 <P>
 </LI>
 <LI>Recent versions of the ZODB allow writing a class with 
@@ -111,8 +105,7 @@ Let's look at each of these rules in detail.
 <UL>
 <LI><A href="node16.html">2.5.1 Modifying Mutable Objects</a>
 <LI><A href="node17.html">2.5.2 Some Special Methods Don't Work</a>
-<LI><A href="node18.html">2.5.3 Fixing <tt class="function">isinstance</tt> and <tt class="function">issubclass</tt></a>
-<LI><A href="node19.html">2.5.4 <tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, and <tt class="method">__setattr__</tt></a>
+<LI><A href="node18.html">2.5.3 <tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, and <tt class="method">__setattr__</tt></a>
 </ul>
 <!--End of Table of Child-Links-->
 
@@ -144,7 +137,7 @@ Let's look at each of these rules in detail.
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node16.html">2.5.1 Modifying Mutable Objects</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node16.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node15.html">
 <LINK REL="up" HREF="node15.html">
 <LINK REL="next" HREF="node17.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -77,10 +78,10 @@ its dirty bit to true.  This is done by setting the
 <tt class="member">_p_changed</tt> attribute of the object to true:
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
 userobj.friends.append(otherUser)
 userobj._p_changed = 1
-</pre></dl>
+</pre></div>
 
 <P>
 An obsolete way of doing this that's still supported is calling the
@@ -98,11 +99,11 @@ an <tt class="method">add_friend()</tt> modifier method to the class.  <tt class
 would then look like this:
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
     def add_friend(self, friend):
         self.friends.append(otherUser)
         self._p_changed = 1
-</pre></dl>
+</pre></div>
 
 <P>
 Alternatively, you could use a ZODB-aware list or mapping type that
@@ -141,7 +142,7 @@ and may make it into a future upstream release of Zope.
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node17.html">2.5.2 Some Special Methods</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node17.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node16.html">
 <LINK REL="up" HREF="node15.html">
 <LINK REL="next" HREF="node18.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -42,7 +43,7 @@
 </tr></table>
 <b class="navlabel">Previous:</b> <a class="sectref" HREF="node16.html">2.5.1 Modifying Mutable Objects</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node18.html">2.5.3 Fixing isinstance and</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node18.html">2.5.3 __getattr__, __delattr__, and</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
@@ -77,13 +78,13 @@ instances, which means that <code>type(obj) == types.InstanceType</code>.
 The code inside the Python interpreter looks like this:
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
 /* Code to compare objects v and w */
 if (PyInstance_Check(v) || PyInstance_Check(w))
         return PyInstance_DoBinOp(v, w, "__cmp__", "__rcmp__", do_cmp);
 /* Do usual Python comparison of v,w */
 c = PyObject_Compare(v, w);
-</pre></dl>
+</pre></div>
 
 <P>
 While ExtensionClasses try to behave as much like regular Python
@@ -120,9 +121,9 @@ will repair this.
 </tr></table>
 <b class="navlabel">Previous:</b> <a class="sectref" HREF="node16.html">2.5.1 Modifying Mutable Objects</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node18.html">2.5.3 Fixing isinstance and</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node18.html">2.5.3 __getattr__, __delattr__, and</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node18.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>2.5.3 Fixing isinstance and issubclass</title>
-<META NAME="description" CONTENT="2.5.3 Fixing isinstance and issubclass">
+<title>2.5.3 __getattr__, __delattr__, and __setattr__</title>
+<META NAME="description" CONTENT="2.5.3 __getattr__, __delattr__, and __setattr__">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node19.html">
 <LINK REL="previous" HREF="node17.html">
 <LINK REL="up" HREF="node15.html">
 <LINK REL="next" HREF="node19.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -42,112 +42,24 @@
 </tr></table>
 <b class="navlabel">Previous:</b> <a class="sectref" HREF="node17.html">2.5.2 Some Special Methods</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node19.html">2.5.4 __getattr__, __delattr__, and</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node19.html">2.6 Writing Persistent Classes</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
 <H3><A NAME="SECTION000353000000000000000">
-2.5.3 Fixing <tt class="function">isinstance</tt> and <tt class="function">issubclass</tt></A>
+2.5.3 <tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, and <tt class="method">__setattr__</tt></A>
 </H3>
 
 <P>
-Python's built-in functions 
-<tt class="function">isinstance()</tt> and <tt class="function">issubclass</tt> don't
-work on ExtensionClass instances, for much the same reason that 
-<tt class="method">__cmp__</tt> is never called; in some bits of the Python core code,
-branches are taken only if an object is of the <tt class="class">InstanceType</tt>
-type, and this can never be true for an ExtensionClass instance.
-Python 2.1 tried to fix this, and changed these functions slightly in
-an effort to make them work for ExtensionClasses; unfortunately, the
-changes didn't work.
-
-<P>
-The solution is to use customized versions of these functions that
-handle ExtensionClasses specially and fall back to the built-in
-version otherwise.  Here are the versions we've written at the MEMS Exchange:
-
-<P>
-<dl><dd><pre class="verbatim">
-# The built-in 'isinstance()' and 'issubclass()' won't work on
-# ExtensionClasses, so you have to use the versions supplied here.
-# (But those versions work fine on regular instances and classes too,
-# so you should *always* use them.)
-
-def issubclass (class1, class2):
-    """A version of 'issubclass' that works with extension classes
-    as well as regular Python classes.
-    """
-
-    # Both class objects are regular Python classes, so use the
-    # built-in 'issubclass()'.
-    if type(class1) is ClassType and type(class2) is ClassType:
-        return __builtin__.issubclass(class1, class2)
-
-    # Both so-called class objects have a '__bases__' attribute: ie.,
-    # they aren't regular Python classes, but they sure look like them.
-    # Assume they are extension classes and reimplement what the builtin
-    # 'issubclass()' does behind the scenes.
-    elif hasattr(class1, '__bases__') and hasattr(class2, '__bases__'):
-        # XXX it appears that "ec.__class__ is type(ec)" for an
-        # extension class 'ec': could we/should we use this as an
-        # additional check for extension classes?
-
-        # Breadth-first traversal of class1's superclass tree.  Order
-        # doesn't matter because we're just looking for a "yes/no"
-        # answer from the tree; if we were trying to resolve a name,
-        # order would be important!
-        stack = [class1]
-        while stack:
-            if stack[0] is class2:
-                return 1
-            stack.extend(list(stack[0].__bases__))
-            del stack[0]
-        else:
-            return 0
-
-    # Not a regular class, not an extension class: blow up for consistency
-    # with builtin 'issubclass()"
-    else:
-        raise TypeError, "arguments must be class or ExtensionClass objects"
-
-# issubclass ()
-
-def isinstance (object, klass):
-    """A version of 'isinstance' that works with extension classes
-    as well as regular Python classes."""
-
-    if type(klass) is TypeType:
-        return __builtin__.isinstance(object, klass)
-    elif hasattr(object, '__class__'):
-        return issubclass(object.__class__, klass)
-    else:
-        return 0
-</pre></dl>
-
-<P>
-I'd recommend putting these functions in a module that always gets
-imported.  The convention on my work project is to put them in
-<span class="file">mems/lib/base.py</span>, which contains various fundamental classes
-and functions for our system, and access them like this:
-
-<P>
-<dl><dd><pre class="verbatim">
-from mems.lib import base
-...
-if base.isinstance(object, Class): ...
-</pre></dl>
-
-<P>
-Don't insert the modified functions into Python's
-<tt class="module">__builtin__</tt> module, or import just the
-<tt class="function">isinstance()</tt> and <tt class="function">issubclass</tt> functions.  
-If you consistently use <tt class="function">base.isinstance()</tt>, then forgetting
-to import the <tt class="module">base</tt> module will result in a
-<tt class="exception">NameError</tt> exception.  In the
-case of a forgotten import, calling the functions directly would use
-Python's built-in versions, leading to subtle bugs that might not be
-noticed for some time.
+Recent versions of ZODB allow writing persistent classes that have
+<tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, or <tt class="method">__setattr__</tt>
+methods.  The one minor complication is that the machinery for
+automatically detecting changes to the object is disabled while the
+<tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, or <tt class="method">__setattr__</tt>
+method is executing.  This means that if the object is modified, the
+object should be marked as dirty by setting the object's
+<tt class="member">_p_changed</tt> method to true.
 
 <P>
 
@@ -177,9 +89,9 @@ noticed for some time.
 </tr></table>
 <b class="navlabel">Previous:</b> <a class="sectref" HREF="node17.html">2.5.2 Some Special Methods</A>
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node19.html">2.5.4 __getattr__, __delattr__, and</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node19.html">2.6 Writing Persistent Classes</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node19.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>2.5.4 __getattr__, __delattr__, and __setattr__</title>
-<META NAME="description" CONTENT="2.5.4 __getattr__, __delattr__, and __setattr__">
+<title>2.6 Writing Persistent Classes</title>
+<META NAME="description" CONTENT="2.6 Writing Persistent Classes">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="previous" HREF="node18.html">
-<LINK REL="up" HREF="node15.html">
+<LINK REL="previous" HREF="node15.html">
+<LINK REL="up" HREF="node8.html">
 <LINK REL="next" HREF="node20.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -22,7 +23,7 @@
 <td><A HREF="node18.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node15.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node8.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node20.html"><img src="/python/writing/icons/next.gif"
@@ -39,29 +40,33 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node18.html">2.5.3 Fixing isinstance and</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node20.html">2.6 Writing Persistent Classes</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node18.html">2.5.3 __getattr__, __delattr__, and</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node20.html">2.6.1 Changing Instance Attributes</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H3><A NAME="SECTION000354000000000000000">
-2.5.4 <tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, and <tt class="method">__setattr__</tt></A>
-</H3>
+<H2><A NAME="SECTION000360000000000000000">
+2.6 Writing Persistent Classes</A>
+</H2>
 
 <P>
-Recent versions of ZODB allow writing persistent classes that have
-<tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, or <tt class="method">__setattr__</tt>
-methods.  The one minor complication is that the machinery for
-automatically detecting changes to the object is disabled while the
-<tt class="method">__getattr__</tt>, <tt class="method">__delattr__</tt>, or <tt class="method">__setattr__</tt>
-method is executing.  This means that if the object is modified, the
-object should be marked as dirty by setting the object's
-<tt class="member">_p_changed</tt> method to true.
+Now that we've looked at the basics of programming using the ZODB,
+we'll turn to some more subtle tasks that are likely to come up for
+anyone using the ZODB in a production system.
 
 <P>
 
+<p><hr>
+<!--Table of Child-Links-->
+<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
+
+<UL>
+<LI><A href="node20.html">2.6.1 Changing Instance Attributes</a>
+</ul>
+<!--End of Table of Child-Links-->
+
 <DIV CLASS="navigation">
 <p><hr>
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
@@ -69,7 +74,7 @@ object should be marked as dirty by setting the object's
 <td><A HREF="node18.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node15.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node8.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node20.html"><img src="/python/writing/icons/next.gif"
@@ -86,11 +91,11 @@ object should be marked as dirty by setting the object's
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node18.html">2.5.3 Fixing isinstance and</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node15.html">2.5 Rules for Writing</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node20.html">2.6 Writing Persistent Classes</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node18.html">2.5.3 __getattr__, __delattr__, and</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node20.html">2.6.1 Changing Instance Attributes</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node2.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" href="contents.html">
 <LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node3.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -100,7 +101,7 @@ of the guide is always available at
 <b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node3.html">1.1 What is the</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node20.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>2.6 Writing Persistent Classes</title>
-<META NAME="description" CONTENT="2.6 Writing Persistent Classes">
+<title>2.6.1 Changing Instance Attributes</title>
+<META NAME="description" CONTENT="2.6.1 Changing Instance Attributes">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="previous" HREF="node15.html">
-<LINK REL="up" HREF="node8.html">
-<LINK REL="next" HREF="node21.html">
+<LINK REL="previous" HREF="node19.html">
+<LINK REL="up" HREF="node19.html">
+<LINK REL="next" href="zeo.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -22,10 +23,10 @@
 <td><A HREF="node19.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node8.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node19.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
-<td><A HREF="node21.html"><img src="/python/writing/icons/next.gif"
+<td><A href="zeo.html"><img src="/python/writing/icons/next.gif"
   border="0" height="32"
   alt="Next Page" width="32"></A></td>
 <td align="center" width="100%">ZODB/ZEO Programming Guide</td>
@@ -39,33 +40,65 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node19.html">2.5.4 __getattr__, __delattr__, and</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node21.html">2.6.1 Changing Instance Attributes</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node19.html">2.6 Writing Persistent Classes</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node19.html">2.6 Writing Persistent Classes</A>
+<b class="navlabel">Next:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000360000000000000000">
-2.6 Writing Persistent Classes</A>
-</H2>
+<H3><A NAME="SECTION000361000000000000000">
+2.6.1 Changing Instance Attributes</A>
+</H3>
 
 <P>
-Now that we've looked at the basics of programming using the ZODB,
-we'll turn to some more subtle tasks that are likely to come up for
-anyone using the ZODB in a production system.
+Ideally, before making a class persistent you would get its interface
+right the first time, so that no attributes would ever need to be
+added, removed, or have their interpretation change over time.  It's a
+worthy goal, but also an impractical one unless you're gifted with
+perfect knowledge of the future.  Such unnatural foresight can't be
+required of any person, so you therefore have to be prepared to handle
+such structural changes gracefully.  In object-oriented database
+terminology, this is a schema update.  The ZODB doesn't have an actual
+schema specification, but you're changing the software's expectations
+of the data contained by an object, so you're implicitly changing the
+schema.
 
 <P>
+One way to handle such a change is to write a one-time conversion
+program that will loop over every single object in the database and
+update them to match the new schema.  This can be easy if your network
+of object references is quite structured, making it easy to find all
+the instances of the class being modified.  For example, if all
+<tt class="class">User</tt> objects can be found inside a single dictionary or
+BTree, then it would be a simple matter to loop over every
+<tt class="class">User</tt> instance with a <tt class="keyword">for</tt> statement.
+This is more difficult if your object graph is less structured; if
+<tt class="class">User</tt> objects can be found as attributes of any number of
+different class instances, then there's no longer any easy way to find
+them all, short of writing a generalized object traversal function
+that would walk over every single object in a ZODB, checking each one
+to see if it's an instance of <tt class="class">User</tt>.  
+<A NAME="tex2html1"
+  HREF="#foot262"><SUP>1</SUP></A>Some OODBs support a feature called extents, which allow quickly
+finding all the instances of a given class, no matter where they are
+in the object graph; unfortunately the ZODB doesn't offer extents as a
+feature.
 
-<p><hr>
-<!--Table of Child-Links-->
-<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
+<P>
+XXX Rest of section not written yet: __getstate__/__setstate__
 
-<UL>
-<LI><A href="node21.html">2.6.1 Changing Instance Attributes</a>
-</ul>
-<!--End of Table of Child-Links-->
+<P>
+<BR><HR><H4>Footnotes</H4>
+<DL>
+<DT><A NAME="foot262">...User.  
+</A><A NAME="foot262"
+ HREF="node20.html#tex2html1"><SUP>1</SUP></A>
+<DD>XXX is there a convenience method for walking the object graph hiding
+somewhere inside DC's code?  Should there be a utility method for
+doing this?  Should I write one and include it in this section?
 
+</DL>
 <DIV CLASS="navigation">
 <p><hr>
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
@@ -73,10 +106,10 @@ anyone using the ZODB in a production system.
 <td><A HREF="node19.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node8.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node19.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
-<td><A HREF="node21.html"><img src="/python/writing/icons/next.gif"
+<td><A href="zeo.html"><img src="/python/writing/icons/next.gif"
   border="0" height="32"
   alt="Next Page" width="32"></A></td>
 <td align="center" width="100%">ZODB/ZEO Programming Guide</td>
@@ -90,11 +123,11 @@ anyone using the ZODB in a production system.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node19.html">2.5.4 __getattr__, __delattr__, and</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node8.html">2 ZODB Programming</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node21.html">2.6.1 Changing Instance Attributes</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node19.html">2.6 Writing Persistent Classes</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node19.html">2.6 Writing Persistent Classes</A>
+<b class="navlabel">Next:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node22.html

+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
+<html>
+<head>
+<title>3.1 How ZEO Works</title>
+<META NAME="description" CONTENT="3.1 How ZEO Works">
+<META NAME="keywords" CONTENT="zodb">
+<META NAME="resource-type" CONTENT="document">
+<META NAME="distribution" CONTENT="global">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
+<link rel="first" href="zodb.html">
+<link rel="contents" href="contents.html" title="Contents">
+
+<LINK REL="next" HREF="node23.html">
+<LINK REL="previous" href="zeo.html">
+<LINK REL="up" href="zeo.html">
+<LINK REL="next" HREF="node23.html">
+<meta name='aesop' content='information'>
+</head>
+<body>
+<DIV CLASS="navigation">
+<table align="center" width="100%" cellpadding="0" cellspacing="2">
+<tr>
+<td><A href="zeo.html"><img src="/python/writing/icons/previous.gif"
+  border="0" height="32"
+  alt="Previous Page" width="32"></A></td>
+<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
+  border="0" height="32"
+  alt="Up One Level" width="32"></A></td>
+<td><A HREF="node23.html"><img src="/python/writing/icons/next.gif"
+  border="0" height="32"
+  alt="Next Page" width="32"></A></td>
+<td align="center" width="100%">ZODB/ZEO Programming Guide</td>
+<td><A href="contents.html"><img src="/python/writing/icons/contents.gif"
+  border="0" height="32"
+  alt="Contents" width="32"></A></td>
+<td><img src="/python/writing/icons/blank.gif"
+  border="0" height="32"
+  alt="" width="32"></td>
+<td><img src="/python/writing/icons/blank.gif"
+  border="0" height="32"
+  alt="" width="32"></td>
+</tr></table>
+<b class="navlabel">Previous:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<br><hr>
+</DIV>
+<!--End of Navigation Panel-->
+
+<H2><A NAME="SECTION000410000000000000000">
+3.1 How ZEO Works</A>
+</H2>
+
+<P>
+The ZODB, as I've described it so far, can only be used within a
+single Python process (though perhaps with multiple threads).  ZEO,
+Zope Enterprise Objects, extends the ZODB machinery to provide access
+to objects over a network.  The name "Zope Enterprise Objects" is a
+bit misleading; ZEO can be used to store Python objects and access
+them in a distributed fashion without Zope ever entering the picture.
+The combination of ZEO and ZODB is essentially a Python-specific
+object database.
+
+<P>
+ZEO consists of about 6000 lines of Python code, excluding tests.  The
+code is relatively small because it contains only code for a TCP/IP
+server, and for a new type of Storage, <tt class="class">ClientStorage</tt>.
+<tt class="class">ClientStorage</tt> simply makes remote procedure calls to the
+server, which then passes them on a regular <tt class="class">Storage</tt> class such
+as <tt class="class">FileStorage</tt>.  The following diagram lays out the system:
+
+<P>
+XXX insert diagram here later
+
+<P>
+Any number of processes can create a <tt class="class">ClientStorage</tt>
+instance, and any number of threads in each process can be using that
+instance.  <tt class="class">ClientStorage</tt> aggressively caches objects
+locally, so in order to avoid using stale data.  The ZEO server sends
+an invalidation message to all the connected <tt class="class">ClientStorage</tt>
+instances on every write operation.  The invalidation message contains
+the object ID for each object that's been modified, letting the
+<tt class="class">ClientStorage</tt> instances delete the old data for the
+given object from their caches.
+
+<P>
+This design decision has some consequences you should be aware of.
+First, while ZEO isn't tied to Zope, it was first written for use with
+Zope, which stores HTML, images, and program code in the database.  As
+a result, reads from the database are <i>far</i> more frequent than
+writes, and ZEO is therefore better suited for read-intensive
+applications.  If every <tt class="class">ClientStorage</tt> is writing to the
+database all the time, this will result in a storm of invalidate
+messages being sent, and this might take up more processing time than
+the actual database operations themselves.<A NAME="tex2html2"
+  HREF="#foot429"><SUP>2</SUP></A>
+<P>
+On the other hand, for applications that have few writes in comparison
+to the number of read accesses, this aggressive caching can be a major
+win.  Consider a Slashdot-like discussion forum that divides the load
+among several Web servers.  If news items and postings are represented
+by objects and accessed through ZEO, then the most heavily accessed
+objects - the most recent or most popular postings - will very
+quickly wind up in the caches of the
+<tt class="class">ClientStorage</tt> instances on the front-end servers.  The
+back-end ZEO server will do relatively little work, only being called
+upon to return the occasional older posting that's requested, and to
+send the occasional invalidate message when a new posting is added.
+The ZEO server isn't going to be contacted for every single request,
+so its workload will remain manageable.
+
+<P>
+<BR><HR><H4>Footnotes</H4>
+<DL>
+<DT><A NAME="foot429">... themselves.</A><A NAME="foot429"
+ HREF="node22.html#tex2html2"><SUP>2</SUP></A>
+<DD>These messages are
+small and sent in batches, so there would need to be a lot of writes
+before it became a problem.
+
+</DL>
+<DIV CLASS="navigation">
+<p><hr>
+<table align="center" width="100%" cellpadding="0" cellspacing="2">
+<tr>
+<td><A href="zeo.html"><img src="/python/writing/icons/previous.gif"
+  border="0" height="32"
+  alt="Previous Page" width="32"></A></td>
+<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
+  border="0" height="32"
+  alt="Up One Level" width="32"></A></td>
+<td><A HREF="node23.html"><img src="/python/writing/icons/next.gif"
+  border="0" height="32"
+  alt="Next Page" width="32"></A></td>
+<td align="center" width="100%">ZODB/ZEO Programming Guide</td>
+<td><A href="contents.html"><img src="/python/writing/icons/contents.gif"
+  border="0" height="32"
+  alt="Contents" width="32"></A></td>
+<td><img src="/python/writing/icons/blank.gif"
+  border="0" height="32"
+  alt="" width="32"></td>
+<td><img src="/python/writing/icons/blank.gif"
+  border="0" height="32"
+  alt="" width="32"></td>
+</tr></table>
+<b class="navlabel">Previous:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<hr>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
+</DIV>
+<!--End of Navigation Panel-->
+
+</BODY>
+</HTML>

doc/guide/zodb/node23.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>3.1 How ZEO Works</title>
-<META NAME="description" CONTENT="3.1 How ZEO Works">
+<title>3.2 Installing ZEO</title>
+<META NAME="description" CONTENT="3.2 Installing ZEO">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node24.html">
-<LINK REL="previous" href="zeo.html">
+<LINK REL="next" HREF="node26.html">
+<LINK REL="previous" HREF="node22.html">
 <LINK REL="up" href="zeo.html">
 <LINK REL="next" HREF="node24.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
 <tr>
-<td><A href="zeo.html"><img src="/python/writing/icons/previous.gif"
+<td><A HREF="node22.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
 <td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
@@ -40,83 +41,38 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node22.html">3.1 How ZEO Works</A>
 <b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node24.html">3.2.1 Requirements</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000410000000000000000">
-3.1 How ZEO Works</A>
+<H2><A NAME="SECTION000420000000000000000">
+3.2 Installing ZEO</A>
 </H2>
 
 <P>
-The ZODB, as I've described it so far, can only be used within a
-single Python process (though perhaps with multiple threads).  ZEO,
-Zope Enterprise Objects, extends the ZODB machinery to provide access
-to objects over a network.  The name "Zope Enterprise Objects" is a
-bit misleading; ZEO can be used to store Python objects and access
-them in a distributed fashion without Zope ever entering the picture.
-The combination of ZEO and ZODB is essentially a Python-specific
-object database.
-
-<P>
-ZEO consists of about 1400 lines of Python code.  The code is
-relatively small because it contains only code for a TCP/IP server,
-and for a new type of Storage, <tt class="class">ClientStorage</tt>.
-<tt class="class">ClientStorage</tt> doesn't use disk files at all; it simply
-makes remote procedure calls to the server, which then passes them on
-a regular <tt class="class">Storage</tt> class such as <tt class="class">FileStorage</tt>.  The
-following diagram lays out the system:
-
-<P>
-XXX insert diagram here later
+This section covers how to install the ZEO package, and how to 
+configure and run a ZEO Storage Server on a machine. 
 
 <P>
-Any number of processes can create a <tt class="class">ClientStorage</tt>
-instance, and any number of threads in each process can be using that
-instance.  <tt class="class">ClientStorage</tt> aggressively caches objects
-locally, so in order to avoid using stale data, the ZEO server sends
-an invalidate message to all the connected <tt class="class">ClientStorage</tt>
-instances on every write operation.  The invalidate message contains
-the object ID for each object that's been modified, letting the
-<tt class="class">ClientStorage</tt> instances delete the old data for the
-given object from their caches.
 
-<P>
-This design decision has some consequences you should be aware of.
-First, while ZEO isn't tied to Zope, it was first written for use with
-Zope, which stores HTML, images, and program code in the database.  As
-a result, reads from the database are <i>far</i> more frequent than
-writes, and ZEO is therefore better suited for read-intensive
-applications.  If every <tt class="class">ClientStorage</tt> is writing to the
-database all the time, this will result in a storm of invalidate
-messages being sent, and this might take up more processing time than
-the actual database operations themselves.
-
-<P>
-On the other hand, for applications that have few writes in comparison
-to the number of read accesses, this aggressive caching can be a major
-win.  Consider a Slashdot-like discussion forum that divides the load
-among several Web servers.  If news items and postings are represented
-by objects and accessed through ZEO, then the most heavily accessed
-objects - the most recent or most popular postings - will very
-quickly wind up in the caches of the
-<tt class="class">ClientStorage</tt> instances on the front-end servers.  The
-back-end ZEO server will do relatively little work, only being called
-upon to return the occasional older posting that's requested, and to
-send the occasional invalidate message when a new posting is added.
-The ZEO server isn't going to be contacted for every single request,
-so its workload will remain manageable.
+<p><hr>
+<!--Table of Child-Links-->
+<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
 
-<P>
+<UL>
+<LI><A href="node24.html">3.2.1 Requirements</a>
+<LI><A href="node25.html">3.2.2 Running a server</a>
+</ul>
+<!--End of Table of Child-Links-->
 
 <DIV CLASS="navigation">
 <p><hr>
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
 <tr>
-<td><A href="zeo.html"><img src="/python/writing/icons/previous.gif"
+<td><A HREF="node22.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
 <td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
@@ -136,11 +92,11 @@ so its workload will remain manageable.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node22.html">3.1 How ZEO Works</A>
 <b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node24.html">3.2.1 Requirements</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node24.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>3.2 Installing ZEO</title>
-<META NAME="description" CONTENT="3.2 Installing ZEO">
+<title>3.2.1 Requirements</title>
+<META NAME="description" CONTENT="3.2.1 Requirements">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node27.html">
+<LINK REL="next" HREF="node25.html">
 <LINK REL="previous" HREF="node23.html">
-<LINK REL="up" href="zeo.html">
+<LINK REL="up" HREF="node23.html">
 <LINK REL="next" HREF="node25.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node23.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node23.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node25.html"><img src="/python/writing/icons/next.gif"
@@ -40,33 +41,23 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node23.html">3.1 How ZEO Works</A>
-<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node25.html">3.2.1 Requirements</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node25.html">3.2.2 Running a server</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000420000000000000000">
-3.2 Installing ZEO</A>
-</H2>
+<H3><A NAME="SECTION000421000000000000000">
+3.2.1 Requirements</A>
+</H3>
 
 <P>
-This section covers how to install the ZEO package, and how to 
-configure and run a ZEO Storage Server on a machine. 
+The ZEO server software is included in ZODB3.  As with the rest of
+ZODB3, you'll need Python 2.1 or higher.
 
 <P>
 
-<p><hr>
-<!--Table of Child-Links-->
-<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
-
-<UL>
-<LI><A href="node25.html">3.2.1 Requirements</a>
-<LI><A href="node26.html">3.2.2 Installation</a>
-</ul>
-<!--End of Table of Child-Links-->
-
 <DIV CLASS="navigation">
 <p><hr>
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
@@ -74,7 +65,7 @@ configure and run a ZEO Storage Server on a machine.
 <td><A HREF="node23.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node23.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node25.html"><img src="/python/writing/icons/next.gif"
@@ -91,11 +82,11 @@ configure and run a ZEO Storage Server on a machine.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node23.html">3.1 How ZEO Works</A>
-<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node25.html">3.2.1 Requirements</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node25.html">3.2.2 Running a server</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node25.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>3.2.1 Requirements</title>
-<META NAME="description" CONTENT="3.2.1 Requirements">
+<title>3.2.2 Running a server</title>
+<META NAME="description" CONTENT="3.2.2 Running a server">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
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-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node26.html">
 <LINK REL="previous" HREF="node24.html">
-<LINK REL="up" HREF="node24.html">
+<LINK REL="up" HREF="node23.html">
 <LINK REL="next" HREF="node26.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +23,7 @@
 <td><A HREF="node24.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node24.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node23.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node26.html"><img src="/python/writing/icons/next.gif"
@@ -40,30 +40,23 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node26.html">3.2.2 Installation</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node24.html">3.2.1 Requirements</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node26.html">3.3 Testing the ZEO</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H3><A NAME="SECTION000421000000000000000">
-3.2.1 Requirements</A>
+<H3><A NAME="SECTION000422000000000000000">
+3.2.2 Running a server</A>
 </H3>
 
 <P>
-To run a ZEO server, you'll need Python 1.5.2 or 2.0, and the ZODB
-packages from <a class="url" href="http://www.amk.ca/files/zodb/">http://www.amk.ca/files/zodb/</a>have to be installed.  
-
-<P>
-<i>Note for Python 1.5.2 users</i>: ZEO requires updated versions
-of the <tt class="module">asyncore.py</tt> and <tt class="module">asynchat.py</tt> modules that are
-included in 1.5.2's standard library.  Current versions of the ZODB
-distribution install private versions of these modules, so you
-shouldn't need to grab updated versions yourself.  (The symptom of
-this problem is a traceback on attempting to run a ZEO client program:
-the traceback is ``TypeError: too many arguments; expected 2, got 3''
-around line 100 of <span class="file">smac.py</span>.
+The start.py script in the ZEO directory can be used to start a
+server.  Run it with the -h option to see the various values.  If
+you're just experimenting, a good choise is to use 
+<code>python ZEO/start.py -D -U /tmp/zeosocket</code> to run ZEO in
+debug mode and with a Unix domain socket.
 
 <P>
 
@@ -74,7 +67,7 @@ around line 100 of <span class="file">smac.py</span>.
 <td><A HREF="node24.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node24.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node23.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node26.html"><img src="/python/writing/icons/next.gif"
@@ -91,11 +84,11 @@ around line 100 of <span class="file">smac.py</span>.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node26.html">3.2.2 Installation</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node24.html">3.2.1 Requirements</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node23.html">3.2 Installing ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node26.html">3.3 Testing the ZEO</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

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 <html>
 <head>
-<title>3.2.2 Installation</title>
-<META NAME="description" CONTENT="3.2.2 Installation">
+<title>3.3 Testing the ZEO Installation</title>
+<META NAME="description" CONTENT="3.3 Testing the ZEO Installation">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
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-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="previous" HREF="node25.html">
-<LINK REL="up" HREF="node24.html">
 <LINK REL="next" HREF="node27.html">
+<LINK REL="previous" HREF="node23.html">
+<LINK REL="up" href="zeo.html">
+<LINK REL="next" HREF="node27.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -22,7 +24,7 @@
 <td><A HREF="node25.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node24.html"><img src="/python/writing/icons/up.gif"
+<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node27.html"><img src="/python/writing/icons/next.gif"
@@ -39,24 +41,54 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node25.html">3.2.1 Requirements</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node27.html">3.3 Configuring and Running</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node25.html">3.2.2 Running a server</A>
+<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node27.html">3.4 ZEO Programming Notes</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H3><A NAME="SECTION000422000000000000000">
-3.2.2 Installation</A>
-</H3>
+<H2><A NAME="SECTION000430000000000000000">
+3.3 Testing the ZEO Installation</A>
+</H2>
+
+<P>
+Once a ZEO server is up and running, using it is just like using ZODB
+with a more conventional disk-based storage; no new programming
+details are introduced by using a remote server.  The only difference
+is that programs must create a <tt class="class">ClientStorage</tt> instance instead
+of a <tt class="class">FileStorage</tt> instance.  From that point onward, ZODB-based
+code is happily unaware that objects are being retrieved from a ZEO
+server, and not from the local disk.
+
+<P>
+As an example, and to test whether ZEO is working correctly, try
+running the following lines of code, which will connect to the server,
+add some bits of data to the root of the ZODB, and commits the
+transaction:
+
+<P>
+<div class="verbatim"><pre>
+from ZEO import ClientStorage
+from ZODB import DB
+
+# Change next line to connect to your ZEO server
+addr = ('kronos.example.com', 1975)
+storage = ClientStorage.ClientStorage(addr)
+db = DB(storage)
+conn = db.open()
+root = conn.root()
+
+# Store some things in the root
+root['list'] = ['a', 'b', 1.0, 3]
+root['dict'] = {'a':1, 'b':4}
+
+# Commit the transaction
+get_transaction().commit()
+</pre></div>
 
 <P>
-Installing the ZEO package is easy.  Just run <code>python setup.py
-install</code>.  This will install the ZEO/ package into your Python
-installation, and copy various files into their proper locations:
-<span class="file">zeo.conf</span> will be put into <span class="file">/usr/local/etc/</span>, a <span class="file">zeo</span> startup
-script will be put in <span class="file">/etc/rc.d/init.d/</span>, and the <span class="file">zeod</span>
-daemon program will be placed in <span class="file">/usr/local/bin</span>.
+If this code runs properly, then your ZEO server is working correctly.
 
 <P>
 
@@ -67,7 +99,7 @@ daemon program will be placed in <span class="file">/usr/local/bin</span>.
 <td><A HREF="node25.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node24.html"><img src="/python/writing/icons/up.gif"
+<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node27.html"><img src="/python/writing/icons/next.gif"
@@ -84,11 +116,11 @@ daemon program will be placed in <span class="file">/usr/local/bin</span>.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node25.html">3.2.1 Requirements</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node24.html">3.2 Installing ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node27.html">3.3 Configuring and Running</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node25.html">3.2.2 Running a server</A>
+<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node27.html">3.4 ZEO Programming Notes</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node27.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>3.3 Configuring and Running a ZEO Server</title>
-<META NAME="description" CONTENT="3.3 Configuring and Running a ZEO Server">
+<title>3.4 ZEO Programming Notes</title>
+<META NAME="description" CONTENT="3.4 ZEO Programming Notes">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" HREF="node28.html">
-<LINK REL="previous" HREF="node24.html">
+<LINK REL="previous" HREF="node26.html">
 <LINK REL="up" href="zeo.html">
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+<meta name='aesop' content='information'>
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@@ -40,23 +41,27 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node26.html">3.2.2 Installation</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node26.html">3.3 Testing the ZEO</A>
 <b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node28.html">3.4 Testing the ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node28.html">3.5 Sample Application: chatter.py</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000430000000000000000">
-3.3 Configuring and Running a ZEO Server</A>
+<H2><A NAME="SECTION000440000000000000000">
+3.4 ZEO Programming Notes</A>
 </H2>
 
 <P>
-Edit <code>/usr/local/etc/zeo.conf</code> appropriately for your desired
-setup.  This configuration file controls the port on which ZEO will
-listen for connections, the user and group IDs under which the server
-will be executed, and the location of the concrete <tt class="class">Storage</tt>
-object that will be made network-accessible.
+ZEO is written using <tt class="module">asyncore</tt>, from the Python standard
+library.  It assumes that some part of the user application is running
+an <tt class="module">asyncore</tt> mainloop.  For example, Zope run the loop in a
+separate thread and ZEO uses that.  If your application does not have
+a mainloop, ZEO will not process incoming invalidation messages until
+you make some call into ZEO.  The <tt class="method">Connection.sync</tt> method can
+be used to process pending invalidation messages.  You can call it
+when you want to make sure the <tt class="class">Connection</tt> has the most recent
+version of every object, but you don't have any other work for ZEO to do.
 
 <P>
 
@@ -84,11 +89,11 @@ object that will be made network-accessible.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node26.html">3.2.2 Installation</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node26.html">3.3 Testing the ZEO</A>
 <b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node28.html">3.4 Testing the ZEO</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node28.html">3.5 Sample Application: chatter.py</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node28.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>3.4 Testing the ZEO Installation</title>
-<META NAME="description" CONTENT="3.4 Testing the ZEO Installation">
+<title>3.5 Sample Application: chatter.py</title>
+<META NAME="description" CONTENT="3.5 Sample Application: chatter.py">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node29.html">
 <LINK REL="previous" HREF="node27.html">
 <LINK REL="up" href="zeo.html">
 <LINK REL="next" HREF="node29.html">
+<meta name='aesop' content='information'>
 </head>
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 <DIV CLASS="navigation">
@@ -40,54 +40,154 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node27.html">3.3 Configuring and Running</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node27.html">3.4 ZEO Programming Notes</A>
 <b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node29.html">3.5 ZEO Programming Notes</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
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 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000440000000000000000">
-3.4 Testing the ZEO Installation</A>
+<H2><A NAME="SECTION000450000000000000000">
+3.5 Sample Application: chatter.py</A>
 </H2>
 
 <P>
-Once a ZEO server is up and running, using it is just like using ZODB
-with a more conventional disk-based storage; no new programming
-details are introduced by using a remote server.  The only difference
-is that programs must create a <tt class="class">ClientStorage</tt> instance instead
-of a <tt class="class">FileStorage</tt> instance.  From that point onward, ZODB-based
-code is happily unaware that objects are being retrieved from a ZEO
-server, and not from the local disk.
+For an example application, we'll build a little chat application.
+What's interesting is that none of the application's code deals with
+network programming at all; instead, an object will hold chat
+messages, and be magically shared between all the clients through ZEO.
+I won't present the complete script here; it's included in my ZODB
+distribution, and you can download it from
+<a class="url" href="http://www.amk.ca/zodb/demos/">http://www.amk.ca/zodb/demos/</a>.  Only the interesting portions of
+the code will be covered here.
+
+<P>
+The basic data structure is the <tt class="class">ChatSession</tt> object,
+which provides an <tt class="method">add_message()</tt> method that adds a
+message, and a <tt class="method">new_messages()</tt> method that returns a list
+of new messages that have accumulated since the last call to
+<tt class="method">new_messages()</tt>.  Internally, <tt class="class">ChatSession</tt>
+maintains a B-tree that uses the time as the key, and stores the
+message as the corresponding value.
+
+<P>
+The constructor for <tt class="class">ChatSession</tt> is pretty simple; it simply
+creates an attribute containing a B-tree:
+
+<P>
+<div class="verbatim"><pre>
+class ChatSession(Persistent):
+    def __init__(self, name):
+        self.name = name
+        # Internal attribute: _messages holds all the chat messages.        
+        self._messages = BTrees.OOBTree.OOBTree()
+</pre></div>
+
+<P>
+<tt class="method">add_message()</tt> has to add a message to the
+<code>_messages</code> B-tree.  A complication is that it's possible
+that some other client is trying to add a message at the same time;
+when this happens, the client that commits first wins, and the second
+client will get a <tt class="exception">ConflictError</tt> exception when it tries to
+commit.  For this application, <tt class="exception">ConflictError</tt> isn't serious
+but simply means that the operation has to be retried; other
+applications might treat it as a fatal error.  The code uses
+<code>try...except...else</code> inside a <code>while</code> loop,
+breaking out of the loop when the commit works without raising an
+exception.
+
+<P>
+<div class="verbatim"><pre>
+    def add_message(self, message):
+        """Add a message to the channel.
+        message -- text of the message to be added
+        """
+
+        while 1:
+            try:
+                now = time.time()
+                self._messages[now] = message
+                get_transaction().commit()
+            except ConflictError:
+                # Conflict occurred; this process should pause and
+                # wait for a little bit, then try again.
+                time.sleep(.2)
+                pass
+            else:
+                # No ConflictError exception raised, so break
+                # out of the enclosing while loop.
+                break
+        # end while
+</pre></div>
+
+<P>
+<tt class="method">new_messages()</tt> introduces the use of <i>volatile</i>
+attributes.  Attributes of a persistent object that begin with
+<code>_v_</code> are considered volatile and are never stored in the
+database.  <tt class="method">new_messages()</tt> needs to store the last time
+the method was called, but if the time was stored as a regular
+attribute, its value would be committed to the database and shared
+with all the other clients.  <tt class="method">new_messages()</tt> would then
+return the new messages accumulated since any other client called
+<tt class="method">new_messages()</tt>, which isn't what we want.
+
+<P>
+<div class="verbatim"><pre>
+    def new_messages(self):
+        "Return new messages."
+
+        # self._v_last_time is the time of the most recent message
+        # returned to the user of this class. 
+        if not hasattr(self, '_v_last_time'):
+            self._v_last_time = 0
+
+        new = []
+        T = self._v_last_time
+
+        for T2, message in self._messages.items():
+            if T2 &gt; T:
+                new.append(message)
+                self._v_last_time = T2
+
+        return new
+</pre></div>
 
 <P>
-As an example, and to test whether ZEO is working correctly, try
-running the following lines of code, which will connect to the server,
-add some bits of data to the root of the ZODB, and commits the
-transaction:
+This application is interesting because it uses ZEO to easily share a
+data structure; ZEO and ZODB are being used for their networking
+ability, not primarily for their data storage ability.  I can foresee
+many interesting applications using ZEO in this way:
 
 <P>
-<dl><dd><pre class="verbatim">
-from ZEO import ClientStorage
-from ZODB import DB
 
-# Change next line to connect to your ZEO server
-addr = ('kronos.example.com', 1975)
-storage = ClientStorage.ClientStorage(addr)
-db = DB(storage)
-conn = db.open()
-root = conn.root()
+<UL>
+<LI>With a Tkinter front-end, and a cleverer, more scalable data
+  structure, you could build a shared whiteboard using the same
+  technique.
+
+<P>
+</LI>
+<LI>A shared chessboard object would make writing a networked chess
+  game easy.  
 
-# Store some things in the root
-root['list'] = ['a', 'b', 1.0, 3]
-root['dict'] = {'a':1, 'b':4}
+<P>
+</LI>
+<LI>You could create a Python class containing a CD's title and
+  track information.  To make a CD database, a read-only ZEO server
+  could be opened to the world, or an HTTP or XML-RPC interface could
+  be written on top of the ZODB.
 
-# Commit the transaction
-get_transaction().commit()
-</pre></dl>
+<P>
+</LI>
+<LI>A program like Quicken could use a ZODB on the local disk to
+  store its data.  This avoids the need to write and maintain
+  specialized I/O code that reads in your objects and writes them out;
+  instead you can concentrate on the problem domain, writing objects
+  that represent cheques, stock portfolios, or whatever.
 
 <P>
-If this code runs properly, then your ZEO server is working correctly.
+</LI>
+</UL>
 
 <P>
 
@@ -115,11 +215,11 @@ If this code runs properly, then your ZEO server is working correctly.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node27.html">3.3 Configuring and Running</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node27.html">3.4 ZEO Programming Notes</A>
 <b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node29.html">3.5 ZEO Programming Notes</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node29.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>3.5 ZEO Programming Notes</title>
-<META NAME="description" CONTENT="3.5 ZEO Programming Notes">
+<title>4 Transactions and Versioning</title>
+<META NAME="description" CONTENT="4 Transactions and Versioning">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
+<LINK REL="next" HREF="node34.html">
+<LINK REL="previous" href="zeo.html">
+<LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node30.html">
-<LINK REL="previous" HREF="node28.html">
-<LINK REL="up" href="zeo.html">
-<LINK REL="next" HREF="node30.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node28.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node30.html"><img src="/python/writing/icons/next.gif"
@@ -40,21 +41,30 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node28.html">3.4 Testing the ZEO</A>
-<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node30.html">3.6 Sample Application: chatter.py</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node28.html">3.5 Sample Application: chatter.py</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node30.html">4.1 Subtransactions</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000450000000000000000">
-3.5 ZEO Programming Notes</A>
-</H2>
+<H1><A NAME="SECTION000500000000000000000">
+4 Transactions and Versioning</A>
+</H1>
 
 <P>
-XXX The Connection.sync() method and its necessity (if it works at all!) 
 
-<P>
+<p><hr>
+<!--Table of Child-Links-->
+<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
+
+<UL>
+<LI><A href="node30.html">4.1 Subtransactions</a>
+<LI><A href="node31.html">4.2 Undoing Changes</a>
+<LI><A href="node32.html">4.3 Versions</a>
+<LI><A href="node33.html">4.4 Multithreaded ZODB Programs</a>
+</ul>
+<!--End of Table of Child-Links-->
 
 <DIV CLASS="navigation">
 <p><hr>
@@ -63,7 +73,7 @@ XXX The Connection.sync() method and its necessity (if it works at all!)
 <td><A HREF="node28.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A href="zeo.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node30.html"><img src="/python/writing/icons/next.gif"
@@ -80,11 +90,11 @@ XXX The Connection.sync() method and its necessity (if it works at all!)
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node28.html">3.4 Testing the ZEO</A>
-<b class="navlabel">Up:</b> <a class="sectref" href="zeo.html">3 ZEO</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node30.html">3.6 Sample Application: chatter.py</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node28.html">3.5 Sample Application: chatter.py</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node30.html">4.1 Subtransactions</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node3.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node2.html">
 <LINK REL="up" HREF="node2.html">
 <LINK REL="next" HREF="node4.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -106,7 +107,7 @@ accessed in a while.
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node2.html">1 Introduction</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node4.html">1.2 OODBs vs. Relational</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node31.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>4 Transactions and Versioning</title>
-<META NAME="description" CONTENT="4 Transactions and Versioning">
+<title>4.2 Undoing Changes</title>
+<META NAME="description" CONTENT="4.2 Undoing Changes">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node36.html">
-<LINK REL="previous" href="zeo.html">
-<LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node32.html">
+<LINK REL="previous" HREF="node30.html">
+<LINK REL="up" HREF="node29.html">
+<LINK REL="next" HREF="node32.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node30.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node29.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node32.html"><img src="/python/writing/icons/next.gif"
@@ -40,31 +41,99 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node30.html">3.6 Sample Application: chatter.py</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node32.html">4.1 Subtransactions</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node30.html">4.1 Subtransactions</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node32.html">4.3 Versions</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H1><A NAME="SECTION000500000000000000000">
-4 Transactions and Versioning</A>
-</H1>
+<H2><A NAME="SECTION000520000000000000000">
+4.2 Undoing Changes</A>
+</H2>
 
 <P>
+Some types of <tt class="class">Storage</tt> support undoing a transaction even after
+it's been committed.  You can tell if this is the case by calling the
+<tt class="method">supportsUndo()</tt> method of the <tt class="class">DB</tt> instance, which
+returns true if the underlying storage supports undo.  Alternatively
+you can call the <tt class="method">supportsUndo()</tt> method on the underlying
+storage instance.
 
-<p><hr>
-<!--Table of Child-Links-->
-<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
+<P>
+If a database supports undo, then the <tt class="method">undoLog(<var>start</var>,
+<var>end</var><big>[</big>, func<big>]</big>)</tt> method on the <tt class="class">DB</tt> instance returns
+the log of past transactions, returning transactions between the times
+<var>start</var> and <var>end</var>, measured in seconds from the epoch.   
+If present, <var>func</var> is a function that acts as a filter on the
+transactions to be returned; it's passed a dictionary representing
+each transaction, and only transactions for which <var>func</var> returns
+true will be included in the list of transactions returned to the
+caller of <tt class="method">undoLog()</tt>.  The dictionary contains keys for
+various properties of the transaction.  The most important keys are
+"<tt class="samp">id</tt>", for the transaction ID, and "<tt class="samp">time</tt>", for the time at
+which the transaction was committed.  
+
+<P>
+<div class="verbatim"><pre>
+&gt;&gt;&gt; print storage.undoLog(0, sys.maxint)
+[{'description': '',
+  'id': 'AzpGEGqU/0QAAAAAAAAGMA',
+  'time': 981126744.98,
+  'user_name': ''},
+ {'description': '',
+  'id': 'AzpGC/hUOKoAAAAAAAAFDQ',
+  'time': 981126478.202,
+  'user_name': ''}
+  ...
+</pre></div>
+
+<P>
+To store a description and a user name on a commit, get the current
+transaction and call the <tt class="method">note(<var>text</var>)</tt> method to store a
+description, and the
+<tt class="method">setUser(<var>user_name</var>)</tt> method to store the user name.  
+While <tt class="method">setUser()</tt> overwrites the current user name and replaces
+it with the new value, the <tt class="method">note()</tt> method always adds the text
+to the transaction's description, so it can be called several times to
+log several different changes made in the course of a single
+transaction.
 
-<UL>
-<LI><A href="node32.html">4.1 Subtransactions</a>
-<LI><A href="node33.html">4.2 Undoing Changes</a>
-<LI><A href="node34.html">4.3 Versions</a>
-<LI><A href="node35.html">4.4 Multithreaded ZODB Programs</a>
-</ul>
-<!--End of Table of Child-Links-->
+<P>
+<div class="verbatim"><pre>
+get_transaction().setUser('amk')
+get_transaction().note('Change ownership')
+</pre></div>
+
+<P>
+To undo a transaction, call the <tt class="method">DB.undo(<var>id</var>)</tt> method,
+passing it the ID of the transaction to undo.  If the transaction
+can't be undone, a <tt class="exception">ZODB.POSException.UndoError</tt> exception
+will be raised, with the message ``non-undoable
+transaction''.  Usually this will happen because later transactions
+modified the objects affected by the transaction you're trying to
+undo.
+
+<P>
+After you call <tt class="method">undo()</tt> you must commit the transaction for the
+undo to actually be applied.
+<A NAME="tex2html3"
+  HREF="#foot583"><SUP>3</SUP></A>  There is one glitch in the undo process.  The thread
+that calls undo may not see the changes to the object until it calls
+<tt class="method">Connection.sync()</tt> or commits another transaction.
+
+<P>
+<BR><HR><H4>Footnotes</H4>
+<DL>
+<DT><A NAME="foot583">... applied.</A><A NAME="foot583"
+ HREF="node31.html#tex2html3"><SUP>3</SUP></A>
+<DD>There are actually two different ways a storage can
+implement the undo feature.  Most of the storages that ship with ZODB
+use the transactional form of undo described in the main text.  Some
+storages may use a non-transactional undo makes changes visible
+immediately.
 
+</DL>
 <DIV CLASS="navigation">
 <p><hr>
 <table align="center" width="100%" cellpadding="0" cellspacing="2">
@@ -72,7 +141,7 @@
 <td><A HREF="node30.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node29.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node32.html"><img src="/python/writing/icons/next.gif"
@@ -89,11 +158,11 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node30.html">3.6 Sample Application: chatter.py</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node32.html">4.1 Subtransactions</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node30.html">4.1 Subtransactions</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node32.html">4.3 Versions</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node32.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>4.1 Subtransactions</title>
-<META NAME="description" CONTENT="4.1 Subtransactions">
+<title>4.3 Versions</title>
+<META NAME="description" CONTENT="4.3 Versions">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" HREF="node33.html">
 <LINK REL="previous" HREF="node31.html">
-<LINK REL="up" HREF="node31.html">
+<LINK REL="up" HREF="node29.html">
 <LINK REL="next" HREF="node33.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node31.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node29.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node33.html"><img src="/python/writing/icons/next.gif"
@@ -40,52 +41,73 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node33.html">4.2 Undoing Changes</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node31.html">4.2 Undoing Changes</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node33.html">4.4 Multithreaded ZODB Programs</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000510000000000000000">
-4.1 Subtransactions</A>
+<H2><A NAME="SECTION000530000000000000000">
+4.3 Versions</A>
 </H2>
 
 <P>
-Subtransactions can be created within a transaction.  Each
-subtransaction can be individually committed and aborted, but the
-changes within a subtransaction are not truly committed until the
-containing transaction is committed.
+While many subtransactions can be contained within a single regular
+transaction, it's also possible to contain many regular transactions
+within a long-running transaction, called a version in ZODB
+terminology.  Inside a version, any number of transactions can be
+created and committed or rolled back, but the changes within a version
+are not made visible to other connections to the same ZODB.
 
 <P>
-The primary purpose of subtransactions is to decrease the memory usage
-of transactions that touch a very large number of objects.  Consider a
-transaction during which 200,000 objects are modified.  All the
-objects that are modified in a single transaction have to remain in
-memory until the transaction is committed, because the ZODB can't
-discard them from the object cache.  This can potentially make the
-memory usage quite large.  With subtransactions, a commit can be be
-performed at intervals, say, every 10,000 objects.  Those 10,000
-objects are then written to permanent storage and can be purged from
-the cache to free more space.
+Not all storages support versions, but you can test for versioning
+ability by calling <tt class="method">supportsVersions()</tt> method of the
+<tt class="class">DB</tt> instance, which returns true if the underlying storage
+supports versioning.
 
 <P>
-To commit a subtransaction instead of a full transaction, 
-pass a true value to the <tt class="method">commit()</tt>
-or <tt class="method">abort()</tt> method of the <tt class="class">Transaction</tt> object.
+A version can be selected when creating the <tt class="class">Connection</tt>
+instance using the <tt class="method">DB.open(<big>[</big><var>version</var><big>]</big>)</tt> method.
+The <var>version</var> argument must be a string that will be used as the
+name of the version.
 
 <P>
-<dl><dd><pre class="verbatim">
-# Commit a subtransaction
-get_transaction().commit(1)	
+<div class="verbatim"><pre>
+vers_conn = db.open(version='Working version')
+</pre></div>
 
-# Abort a subtransaction
-get_transaction().abort(1)
-</pre></dl>
+<P>
+Transactions can then be committed and aborted using this versioned
+connection.  Other connections that don't specify a version, or
+provide a different version name, will not see changes committed
+within the version named "<tt class="samp">Working&nbsp;version</tt>".  To commit or abort a
+version, which will either make the changes visible to all clients or
+roll them back, call the <tt class="method">DB.commitVersion()</tt> or
+<tt class="method">DB.abortVersion()</tt> methods.
+XXX what are the source and dest arguments for?
+
+<P>
+The ZODB makes no attempt to reconcile changes between different
+versions.  Instead, the first version which modifies an object will
+gain a lock on that object.  Attempting to modify the object from a
+different version or from an unversioned connection will cause a
+<tt class="exception">ZODB.POSException.VersionLockError</tt> to be raised:
+
+<P>
+<div class="verbatim"><pre>
+from ZODB.POSException import VersionLockError
+
+try:
+    get_transaction().commit()
+except VersionLockError, (obj_id, version):
+    print ('Cannot commit; object %s '
+           'locked by version %s' % (obj_id, version))
+</pre></div>
 
 <P>
-A new subtransaction is automatically started on committing or
-aborting the previous subtransaction.
+The exception provides the ID of the locked object, and the name of
+the version having a lock on it.
 
 <P>
 
@@ -96,7 +118,7 @@ aborting the previous subtransaction.
 <td><A HREF="node31.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node29.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node33.html"><img src="/python/writing/icons/next.gif"
@@ -113,11 +135,11 @@ aborting the previous subtransaction.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node33.html">4.2 Undoing Changes</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node31.html">4.2 Undoing Changes</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node33.html">4.4 Multithreaded ZODB Programs</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

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 <html>
 <head>
-<title>4.2 Undoing Changes</title>
-<META NAME="description" CONTENT="4.2 Undoing Changes">
+<title>4.4 Multithreaded ZODB Programs</title>
+<META NAME="description" CONTENT="4.4 Multithreaded ZODB Programs">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node34.html">
 <LINK REL="previous" HREF="node32.html">
-<LINK REL="up" HREF="node31.html">
+<LINK REL="up" HREF="node29.html">
 <LINK REL="next" HREF="node34.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +23,7 @@
 <td><A HREF="node32.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node29.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node34.html"><img src="/python/writing/icons/next.gif"
@@ -40,78 +40,22 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node32.html">4.1 Subtransactions</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node34.html">4.3 Versions</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node32.html">4.3 Versions</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000520000000000000000">
-4.2 Undoing Changes</A>
+<H2><A NAME="SECTION000540000000000000000">
+4.4 Multithreaded ZODB Programs</A>
 </H2>
 
 <P>
-Some types of <tt class="class">Storage</tt> support undoing a transaction even after
-it's been committed.  You can tell if this is the case by calling the
-<tt class="method">supportsUndo()</tt> method of the <tt class="class">DB</tt> instance, which
-returns true if the underlying storage supports undo.  Alternatively
-you can call the <tt class="method">supportsUndo()</tt> method on the underlying
-storage instance.
-
-<P>
-If a database supports undo, then the <tt class="method">undoLog(<var>start</var>,
-<var>end</var><big>[</big>, func<big>]</big>)</tt> method on the <tt class="class">DB</tt> instance returns
-the log of past transactions, returning transactions between the times
-<var>start</var> and <var>end</var>, measured in seconds from the epoch.   
-If present, <var>func</var> is a function that acts as a filter on the
-transactions to be returned; it's passed a dictionary representing
-each transaction, and only transactions for which <var>func</var> returns
-true will be included in the list of transactions returned to the
-caller of <tt class="method">undoLog()</tt>.  The dictionary contains keys for
-various properties of the transaction.  The most important keys are
-"<tt class="samp">id</tt>", for the transaction ID, and "<tt class="samp">time</tt>", for the time at
-which the transaction was committed.  
-
-<P>
-<dl><dd><pre class="verbatim">
-&gt;&gt;&gt; print storage.undoLog(0, sys.maxint)
-[{'description': '',
-  'id': 'AzpGEGqU/0QAAAAAAAAGMA',
-  'time': 981126744.98,
-  'user_name': ''},
- {'description': '',
-  'id': 'AzpGC/hUOKoAAAAAAAAFDQ',
-  'time': 981126478.202,
-  'user_name': ''}
-  ...
-</pre></dl>
-
-<P>
-To store a description and a user name on a commit, get the current
-transaction and call the <tt class="method">note(<var>text</var>)</tt> method to store a
-description, and the
-<tt class="method">setUser(<var>user_name</var>)</tt> method to store the user name.  
-While <tt class="method">setUser()</tt> overwrites the current user name and replaces
-it with the new value, the <tt class="method">note()</tt> method always adds the text
-to the transaction's description, so it can be called several times to
-log several different changes made in the course of a single
-transaction.
-
-<P>
-<dl><dd><pre class="verbatim">
-get_transaction().setUser('amk')
-get_transaction().note('Change ownership')
-</pre></dl>
-
-<P>
-To undo a transaction, call the <tt class="method">DB.undo(<var>id</var>)</tt> method,
-passing it the ID of the transaction to undo.  If the transaction
-can't be undone, a <tt class="exception">ZODB.POSException.UndoError</tt> exception
-will be raised, with the message ``non-undoable
-transaction''.  Usually this will happen because later transactions
-modified the objects affected by the transaction you're trying to
-undo.
+ZODB databases can be accessed from multithreaded Python programs.
+The <tt class="class">Storage</tt> and <tt class="class">DB</tt> instances can be shared among
+several threads, as long as individual <tt class="class">Connection</tt> instances
+are created for each thread.  
 
 <P>
 
@@ -122,7 +66,7 @@ undo.
 <td><A HREF="node32.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node29.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node34.html"><img src="/python/writing/icons/next.gif"
@@ -139,11 +83,11 @@ undo.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node32.html">4.1 Subtransactions</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node34.html">4.3 Versions</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node32.html">4.3 Versions</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node29.html">4 Transactions and Versioning</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node34.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>4.3 Versions</title>
-<META NAME="description" CONTENT="4.3 Versions">
+<title>5 Related Modules</title>
+<META NAME="description" CONTENT="5 Related Modules">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
+<LINK REL="next" HREF="node38.html">
+<LINK REL="previous" HREF="node29.html">
+<LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node35.html">
-<LINK REL="previous" HREF="node33.html">
-<LINK REL="up" HREF="node31.html">
-<LINK REL="next" HREF="node35.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node33.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node35.html"><img src="/python/writing/icons/next.gif"
@@ -40,75 +41,33 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node33.html">4.2 Undoing Changes</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node35.html">4.4 Multithreaded ZODB Programs</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node33.html">4.4 Multithreaded ZODB Programs</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node35.html">5.1 ZODB.PersistentMapping</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000530000000000000000">
-4.3 Versions</A>
-</H2>
-
-<P>
-While many subtransactions can be contained within a single regular
-transaction, it's also possible to contain many regular transactions
-within a long-running transaction, called a version in ZODB
-terminology.  Inside a version, any number of transactions can be
-created and committed or rolled back, but the changes within a version
-are not made visible to other connections to the same ZODB.
-
-<P>
-Not all storages support versions, but you can test for versioning
-ability by calling <tt class="method">supportsVersions()</tt> method of the
-<tt class="class">DB</tt> instance, which returns true if the underlying storage
-supports versioning.
-
-<P>
-A version can be selected when creating the <tt class="class">Connection</tt>
-instance using the <tt class="method">DB.open(<big>[</big><var>version</var><big>]</big>)</tt> method.
-The <var>version</var> argument must be a string that will be used as the
-name of the version.
+<H1><A NAME="SECTION000600000000000000000">
+5 Related Modules</A>
+</H1>
 
 <P>
-<dl><dd><pre class="verbatim">
-vers_conn = db.open(version='Working version')
-</pre></dl>
+The ZODB package includes a number of related modules that provide
+useful data types such as BTrees.
 
 <P>
-Transactions can then be committed and aborted using this versioned
-connection.  Other connections that don't specify a version, or
-provide a different version name, will not see changes committed
-within the version named "<tt class="samp">Working&nbsp;version</tt>".  To commit or abort a
-version, which will either make the changes visible to all clients or
-roll them back, call the <tt class="method">DB.commitVersion()</tt> or
-<tt class="method">DB.abortVersion()</tt> methods.
-XXX what are the source and dest arguments for?
 
-<P>
-The ZODB makes no attempt to reconcile changes between different
-versions.  Instead, the first version which modifies an object will
-gain a lock on that object.  Attempting to modify the object from a
-different version or from an unversioned connection will cause a
-<tt class="exception">ZODB.POSException.VersionLockError</tt> to be raised:
-
-<P>
-<dl><dd><pre class="verbatim">
-from ZODB.POSException import VersionLockError
-
-try:
-    get_transaction().commit()
-except VersionLockError, (obj_id, version):
-    print ('Cannot commit; object %s '
-           'locked by version %s' % (obj_id, version))
-</pre></dl>
-
-<P>
-The exception provides the ID of the locked object, and the name of
-the version having a lock on it.
+<p><hr>
+<!--Table of Child-Links-->
+<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
 
-<P>
+<UL>
+<LI><A href="node35.html">5.1 <tt class="module">ZODB.PersistentMapping</tt></a>
+<LI><A href="node36.html">5.2 <tt class="module">ZODB.PersistentList</tt></a>
+<LI><A href="node37.html">5.3 BTrees Package</a>
+</ul>
+<!--End of Table of Child-Links-->
 
 <DIV CLASS="navigation">
 <p><hr>
@@ -117,7 +76,7 @@ the version having a lock on it.
 <td><A HREF="node33.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node35.html"><img src="/python/writing/icons/next.gif"
@@ -134,11 +93,11 @@ the version having a lock on it.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node33.html">4.2 Undoing Changes</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node35.html">4.4 Multithreaded ZODB Programs</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node33.html">4.4 Multithreaded ZODB Programs</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node35.html">5.1 ZODB.PersistentMapping</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node35.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>4.4 Multithreaded ZODB Programs</title>
-<META NAME="description" CONTENT="4.4 Multithreaded ZODB Programs">
+<title>5.1 ZODB.PersistentMapping</title>
+<META NAME="description" CONTENT="5.1 ZODB.PersistentMapping">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
+<LINK REL="next" HREF="node36.html">
 <LINK REL="previous" HREF="node34.html">
-<LINK REL="up" HREF="node31.html">
+<LINK REL="up" HREF="node34.html">
 <LINK REL="next" HREF="node36.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -22,7 +24,7 @@
 <td><A HREF="node34.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node34.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node36.html"><img src="/python/writing/icons/next.gif"
@@ -39,26 +41,33 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node34.html">4.3 Versions</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node36.html">5.2 ZODB.PersistentList</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000540000000000000000">
-4.4 Multithreaded ZODB Programs</A>
+<H2><A NAME="SECTION000610000000000000000">
+5.1 <tt class="module">ZODB.PersistentMapping</tt></A>
 </H2>
 
 <P>
-ZODB databases can be accessed from multithreaded Python programs.
-The <tt class="class">Storage</tt> and <tt class="class">DB</tt> instances can be shared among
-several threads, as long as individual <tt class="class">Connection</tt> instances
-are created for each thread.  
+The <tt class="class">PersistentMapping</tt> class is a wrapper for mapping objects
+that will set the dirty bit when the mapping is modified by setting or
+deleting a key.  
+
+<P>
+<dl><dt><b><a name="l2h-1"><tt class="function">PersistentMapping</tt></a></b>(<var>container = {}</var>)
+<dd>
+Create a <tt class="class">PersistentMapping</tt> object that wraps the 
+mapping object <var>container</var>.  If you don't specify a
+value for <var>container</var>, a regular Python dictionary is used.
+</dl>
 
 <P>
-XXX I can't think of anything else to say about multithreaded ZODB
-programs.  Suggestions?  An example program?
+<tt class="class">PersistentMapping</tt> objects support all the same methods as 
+Python dictionaries do.
 
 <P>
 
@@ -69,7 +78,7 @@ programs.  Suggestions?  An example program?
 <td><A HREF="node34.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node31.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node34.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node36.html"><img src="/python/writing/icons/next.gif"
@@ -86,11 +95,11 @@ programs.  Suggestions?  An example program?
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node34.html">4.3 Versions</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node31.html">4 Transactions and Versioning</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node36.html">5.2 ZODB.PersistentList</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node36.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>5 Related Modules</title>
-<META NAME="description" CONTENT="5 Related Modules">
+<title>5.2 ZODB.PersistentList</title>
+<META NAME="description" CONTENT="5.2 ZODB.PersistentList">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node40.html">
-<LINK REL="previous" HREF="node31.html">
-<LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node37.html">
+<LINK REL="previous" HREF="node35.html">
+<LINK REL="up" HREF="node34.html">
+<LINK REL="next" HREF="node37.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node35.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node34.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node37.html"><img src="/python/writing/icons/next.gif"
@@ -40,33 +41,34 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node35.html">4.4 Multithreaded ZODB Programs</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node37.html">5.1 ZODB.PersistentMapping</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node35.html">5.1 ZODB.PersistentMapping</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node37.html">5.3 BTrees Package</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H1><A NAME="SECTION000600000000000000000">
-5 Related Modules</A>
-</H1>
+<H2><A NAME="SECTION000620000000000000000">
+5.2 <tt class="module">ZODB.PersistentList</tt></A>
+</H2>
 
 <P>
-The ZODB package includes a number of related modules that provide
-useful data types such as BTrees or full-text indexes.
+The <tt class="class">PersistentList</tt> class is a wrapper for mutable sequence objects, 
+much as <tt class="class">PersistentMapping</tt> is a wrapper for mappings.  
 
 <P>
+<dl><dt><b><a name="l2h-2"><tt class="function">PersistentList</tt></a></b>(<var>initlist = []</var>)
+<dd>
+Create a <tt class="class">PersistentList</tt> object that wraps the 
+mutable sequence object <var>initlist</var>.  If you don't specify a
+value for <var>initlist</var>, a regular Python list is used.
+</dl>
 
-<p><hr>
-<!--Table of Child-Links-->
-<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
+<P>
+<tt class="class">PersistentList</tt> objects support all the same methods as 
+Python lists do.
 
-<UL>
-<LI><A href="node37.html">5.1 <tt class="module">ZODB.PersistentMapping</tt></a>
-<LI><A href="node38.html">5.2 <tt class="module">ZODB.PersistentList</tt></a>
-<LI><A href="node39.html">5.3 B-tree Modules</a>
-</ul>
-<!--End of Table of Child-Links-->
+<P>
 
 <DIV CLASS="navigation">
 <p><hr>
@@ -75,7 +77,7 @@ useful data types such as BTrees or full-text indexes.
 <td><A HREF="node35.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node34.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node37.html"><img src="/python/writing/icons/next.gif"
@@ -92,11 +94,11 @@ useful data types such as BTrees or full-text indexes.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node35.html">4.4 Multithreaded ZODB Programs</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node37.html">5.1 ZODB.PersistentMapping</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node35.html">5.1 ZODB.PersistentMapping</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node37.html">5.3 BTrees Package</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node37.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>5.1 ZODB.PersistentMapping</title>
-<META NAME="description" CONTENT="5.1 ZODB.PersistentMapping">
+<title>5.3 BTrees Package</title>
+<META NAME="description" CONTENT="5.3 BTrees Package">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" HREF="node38.html">
 <LINK REL="previous" HREF="node36.html">
-<LINK REL="up" HREF="node36.html">
+<LINK REL="up" HREF="node34.html">
 <LINK REL="next" HREF="node38.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +23,7 @@
 <td><A HREF="node36.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node36.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node34.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node38.html"><img src="/python/writing/icons/next.gif"
@@ -40,33 +40,114 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node38.html">5.2 ZODB.PersistentList</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node36.html">5.2 ZODB.PersistentList</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node38.html">A. Resources</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000610000000000000000">
-5.1 <tt class="module">ZODB.PersistentMapping</tt></A>
+<H2><A NAME="SECTION000630000000000000000">
+5.3 BTrees Package</A>
 </H2>
 
 <P>
-The <tt class="class">PersistentMapping</tt> class is a wrapper for mapping objects
-that will set the dirty bit when the mapping is modified by setting or
-deleting a key.  
+When programming with the ZODB, Python dictionaries aren't always what
+you need.  The most important case is where you want to store a very
+large mapping.  When a Python dictionary is accessed in a ZODB, the
+whole dictionary has to be unpickled and brought into memory.  If
+you're storing something very large, such as a 100,000-entry user
+database, unpickling such a large object will be slow.  BTrees are a
+balanced tree data structure that behave like a mapping but distribute
+keys throughout a number of tree nodes.  The nodes are stored in
+sorted order.  Nodes are then only unpickled and brought into memory
+as they're accessed, so the entire tree doesn't have to occupy memory
+(unless you really are touching every single key).
+
+<P>
+The BTrees package provides a large collection of related data
+structures.  There are variants of the data structures specialized to
+handle integer values, which are faster and use less memory.  There
+are four modules that handle the different variants.  The first two
+letters of the module name specify the types of the keys and values in
+mappings - O for any object and I for integer.  The
+<tt class="module">BTrees.IOBTree</tt> module provides a mapping that accepts integer
+keys and arbitrary objects as values.
+
+<P>
+The four data structures provide by each module are a btree, a bucket,
+a tree set, and a set.  The btree and bucket types are mappings and
+support all the usual mapping methods, e.g. <tt class="function">update()</tt> and
+<tt class="function">keys()</tt>.  The tree set and set types are similar to mappings
+but they have no values; they support the methods that make sense for
+a mapping with no keys, e.g. <tt class="function">keys()</tt> but not
+<tt class="function">items()</tt>.  The bucket and set types are the individual
+building blocks for btrees and tree sets, respectively.  A bucket or
+set can be used when you are sure that it will have few elements.  If
+the data structure will grow large, you should use a btree or tree
+set.
+
+<P>
+The four modules are named <tt class="module">OOBTree</tt>, <tt class="module">IOBTree</tt>,
+<tt class="module">OIBTree</tt>, and <tt class="module">IIBTree</tt>.  The two letter prefixes are
+repeated in the data types names.  The <tt class="module">BTrees.OOBTree</tt> module
+defines the following types: <tt class="class">OOBTree</tt>, <tt class="class">OOBucket</tt>,
+<tt class="class">OOSet</tt>, and <tt class="class">OOTreeSet</tt>.
 
 <P>
-<dl><dt><b><a name="l2h-1"><tt class="function">PersistentMapping</tt></a></b>(<var>container = {}</var>)
-<dd>
-Create a <tt class="class">PersistentMapping</tt> object that wraps the 
-mapping object <var>container</var>.  If you don't specify a
-value for <var>container</var>, a regular Python dictionary is used.
-</dl>
+The <tt class="function">keys()</tt>, <tt class="function">values()</tt>, and <tt class="function">items()</tt>
+methods do not materialize a list with all of the data.  Instead, they
+return lazy sequences that fetch data from the BTree as needed.  They
+also support optional arguments to specify the minium and maximum
+values to return.
 
 <P>
-<tt class="class">PersistentMapping</tt> objects support all the same methods as 
-Python dictionaries do.
+A BTree object supports all the methods you would expect of a mapping
+with a few extensions that exploit the fact that the keys are sorted.
+The example below demonstrates how some of the methods work.  The
+extra methods re <tt class="function">minKey()</tt> and <tt class="function">maxKey()</tt>, which
+find the minimum and maximum key value subject to an optional bound
+argument, and <tt class="function">byValue()</tt>, which returns value, key pairs
+in reversed sorted order subject to an optional minimum bound argument.
+
+<P>
+<div class="verbatim"><pre>
+&gt;&gt;&gt; from BTrees.OOBTree import OOBTree
+&gt;&gt;&gt; t = OOBTree()
+&gt;&gt;&gt; t.update({ 1: "red", 2: "green", 3: "blue", 4: "spades" })
+&gt;&gt;&gt; len(t)
+4
+&gt;&gt;&gt; t[2]
+'green'
+&gt;&gt;&gt; t.keys()
+&lt;OOBTreeItems object at 0x40269098&gt;
+&gt;&gt;&gt; [k for k in t.keys()] # use a listcomp to get a printable sequence
+[1, 2, 3, 4]
+&gt;&gt;&gt; [k for k in t.values()]
+['red', 'green', 'blue', 'spades']
+&gt;&gt;&gt; [k for k in t.values(1, 2)]
+['red', 'green']
+&gt;&gt;&gt; [k for k in t.values(2)]
+['green', 'blue', 'spades']
+&gt;&gt;&gt; t.byValue("glue") # all values &gt; "glue"
+[('spades', 4), ('red', 1), ('green', 2)]
+&gt;&gt;&gt; t.minKey(1.5)
+2
+</pre></div>
+
+<P>
+Each of the modules also defines some functions that operate on
+BTrees - <tt class="function">difference()</tt>, <tt class="function">union()</tt>, and
+<tt class="function">difference()</tt>.  The <tt class="function">difference()</tt> function returns
+a bucket, while the other two methods return a set.
+If the keys are integers, then the module also defines
+<tt class="function">multiunion()</tt>.  If the values are integers, then the module
+also defines <tt class="function">weightedIntersection()</tt> and
+<tt class="function">weighterUnion()</tt>.  The function doc strings describe each
+function briefly.
+
+<P>
+
 
 <P>
 
@@ -77,7 +158,7 @@ Python dictionaries do.
 <td><A HREF="node36.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node36.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node34.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node38.html"><img src="/python/writing/icons/next.gif"
@@ -94,11 +175,11 @@ Python dictionaries do.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node38.html">5.2 ZODB.PersistentList</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node36.html">5.2 ZODB.PersistentList</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node34.html">5 Related Modules</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node38.html">A. Resources</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node38.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>5.2 ZODB.PersistentList</title>
-<META NAME="description" CONTENT="5.2 ZODB.PersistentList">
+<title>A. Resources</title>
+<META NAME="description" CONTENT="A. Resources">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" HREF="node39.html">
-<LINK REL="previous" HREF="node37.html">
-<LINK REL="up" HREF="node36.html">
+<LINK REL="previous" HREF="node34.html">
+<LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node39.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node37.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node36.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node39.html"><img src="/python/writing/icons/next.gif"
@@ -40,32 +41,45 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node37.html">5.1 ZODB.PersistentMapping</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node39.html">5.3 B-tree Modules</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node37.html">5.3 BTrees Package</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000620000000000000000">
-5.2 <tt class="module">ZODB.PersistentList</tt></A>
-</H2>
+<H1><A NAME="SECTION000700000000000000000">
+A. Resources</A>
+</H1>
 
 <P>
-The <tt class="class">PersistentList</tt> class is a wrapper for mutable sequence objects, 
-much as <tt class="class">PersistentMapping</tt> is a wrapper for mappings.  
+ZODB HOWTO, by Michel Pelletier:
 
+<BR>
+Goes into slightly more detail about the rules for writing applications using the ZODB.
+
+<BR><a class="url" href="http://www.zope.org/Members/michel/HowTos/ZODB-How-To">http://www.zope.org/Members/michel/HowTos/ZODB-How-To</a>
+<P>
+Introduction to the Zope Object Database, by Jim Fulton:
+
+<BR>
+Goes into much greater detail, explaining advanced uses of the ZODB and 
+how it's actually implemented.  A definitive reference, and highly recommended.
+
+<BR><a class="url" href="http://www.python.org/workshops/2000-01/proceedings/papers/fulton/zodb3.html">http://www.python.org/workshops/2000-01/proceedings/papers/fulton/zodb3.html</a>
 <P>
-<dl><dt><b><a name="l2h-2"><tt class="function">PersistentList</tt></a></b>(<var>initlist = []</var>)
-<dd>
-Create a <tt class="class">PersistentList</tt> object that wraps the 
-mutable sequence object <var>initlist</var>.  If you don't specify a
-value for <var>initlist</var>, a regular Python list is used.
-</dl>
+Persistent Programing with ZODB, by Jeremy Hylton and Barry Warsaw:
+
+<BR>
+Slides for a tutorial presented at the 10th Python conference.  Covers
+much of the same ground as this guide, with more details in some areas
+and less in others.
 
+<BR><a class="url" href="http://www.zope.org/Members/bwarsaw/ipc10-slides">http://www.zope.org/Members/bwarsaw/ipc10-slides</a>
+<P>
+Download link for ZEO: 
+<BR><a class="url" href="http://www.zope.org/Products/ZEO/">http://www.zope.org/Products/ZEO/</a>
 <P>
-<tt class="class">PersistentList</tt> objects support all the same methods as 
-Python lists do.
 
 <P>
 
@@ -76,7 +90,7 @@ Python lists do.
 <td><A HREF="node37.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node36.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node39.html"><img src="/python/writing/icons/next.gif"
@@ -93,11 +107,11 @@ Python lists do.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node37.html">5.1 ZODB.PersistentMapping</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node39.html">5.3 B-tree Modules</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node37.html">5.3 BTrees Package</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node39.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>5.3 B-tree Modules</title>
-<META NAME="description" CONTENT="5.3 B-tree Modules">
+<title>B. GNU Free Documentation License</title>
+<META NAME="description" CONTENT="B. GNU Free Documentation License">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
+<LINK REL="next" href="about.html">
 <LINK REL="previous" HREF="node38.html">
-<LINK REL="up" HREF="node36.html">
+<LINK REL="up" HREF="zodb.html">
 <LINK REL="next" HREF="node40.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -22,7 +24,7 @@
 <td><A HREF="node38.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node36.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node40.html"><img src="/python/writing/icons/next.gif"
@@ -39,75 +41,52 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node38.html">5.2 ZODB.PersistentList</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node40.html">A. Resources</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node38.html">A. Resources</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node40.html">Preamble</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000630000000000000000">
-5.3 B-tree Modules</A>
-</H2>
+<H1><A NAME="SECTION000800000000000000000">
+B. GNU Free Documentation License</A>
+</H1>
 
 <P>
-When programming with the ZODB, Python dictionaries aren't always what
-you need.  The most important case is where you want to store a very
-large mapping.  When a Python dictionary is accessed in a ZODB, the
-whole dictionary has to be unpickled and brought into memory.  If
-you're storing something very large, such as a 100,000-entry user
-database, unpickling such a large object will be slow.  B-trees are a
-balanced tree data structure that behave like a mapping but distribute
-keys throughout a number of tree nodes.  Nodes are then only unpickled
-and brought into memory as they're accessed, so the entire tree
-doesn't have to occupy memory (unless you really are touching every
-single key).
-
-<P>
-There are four different BTree modules provided.  One of them, the
-<tt class="module">BTree</tt> module, provides the most general data type; the keys
-and values in the B-tree can be any Python object.  Some specialized B-tree
-modules require that the keys, and perhaps even the values, to be of a
-certain type, and provide faster performance because of this limitation.
-
-<P>
-<DL COMPACT>
-<DT> <tt class="module">IOBTree</tt> </DT>
-<DD>requires the keys to be integers.
-The module name reminds you of this; the <tt class="module">IOBTree</tt> module
-maps Integers to Objects.
-
-<P>
-</DD>
-<DT> <tt class="module">OIBTree</tt> </DT>
-<DD>requires the values to be integers,
-mapping Objects to Integers.
-
+Version 1.1, March 2000
+<BR>
 <P>
-</DD>
-<DT> <tt class="module">IIBTree</tt> </DT>
-<DD>is strictest, requiring that both keys and values must be integers.
-
-<P>
-</DD>
-</DL>
-
-<P>
-To use a B-tree, simply import the desired module and call the
-constructor, always named <tt class="function">BTree()</tt>, to get a B-tree
-instance, and then use it like any other mapping:
-
-<P>
-<dl><dd><pre class="verbatim">
-import IIBTree
-iimap = IIBTree.BTree()
-iimap[1972] = 27
-</pre></dl>
+Copyright <SPAN CLASS="MATH"><IMG
+ WIDTH="20" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
+ SRC="img1.gif"
+ ALT="$\copyright$"></SPAN> 2000  Free Software Foundation, Inc.
+<BR>
+59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+<BR>
+Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
 
 <P>
 
+<p><hr>
+<!--Table of Child-Links-->
+<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
 
-<P>
+<UL>
+<LI><A href="node40.html">Preamble</a>
+<LI><A href="node41.html">B..1 Applicability and Definitions</a>
+<LI><A href="node42.html">B..2 Verbatim Copying</a>
+<LI><A href="node43.html">B..3 Copying in Quantity</a>
+<LI><A href="node44.html">B..4 Modifications</a>
+<LI><A href="node45.html">B..5 Combining Documents</a>
+<LI><A href="node46.html">B..6 Collections of Documents</a>
+<LI><A href="node47.html">B..7 Aggregation With Independent Works</a>
+<LI><A href="node48.html">B..8 Translation</a>
+<LI><A href="node49.html">B..9 Termination</a>
+<LI><A href="node50.html">B..10 Future Revisions of This Licence</a>
+<LI><A href="node51.html">ADDENDUM: How to use this License for your documents</a>
+</ul>
+<!--End of Table of Child-Links-->
 
 <DIV CLASS="navigation">
 <p><hr>
@@ -116,7 +95,7 @@ iimap[1972] = 27
 <td><A HREF="node38.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node36.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node40.html"><img src="/python/writing/icons/next.gif"
@@ -133,11 +112,11 @@ iimap[1972] = 27
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node38.html">5.2 ZODB.PersistentList</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node36.html">5 Related Modules</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node40.html">A. Resources</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node38.html">A. Resources</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node40.html">Preamble</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node4.html

@@ -6,8 +6,8 @@
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
@@ -15,6 +15,7 @@
 <LINK REL="previous" HREF="node3.html">
 <LINK REL="up" HREF="node2.html">
 <LINK REL="next" HREF="node5.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -87,7 +88,7 @@ depositing, and 2) how much should be deposited.  You might deposit
 Mapping these structures to a relational database is straightforward:
 
 <P>
-<dl><dd><pre class="verbatim">
+<div class="verbatim"><pre>
 CREATE TABLE runs (
   int      run_id,
   varchar  owner,
@@ -113,7 +114,7 @@ CREATE TABLE parameters (
   FOREIGN KEY(run_id, step_num) 
      REFERENCES operations(run_id, step_num),
 );
-</pre></dl>
+</pre></div>
 
 <P>
 In Python, you would write three classes named <tt class="class">Run</tt>,
@@ -208,7 +209,7 @@ runs, therefore, is still inefficient, but not grossly inefficient.
 <b class="navlabel">Up:</b> <a class="sectref" HREF="node2.html">1 Introduction</A>
 <b class="navlabel">Next:</b> <a class="sectref" HREF="node5.html">1.3 What is ZEO?</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node40.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>A. Resources</title>
-<META NAME="description" CONTENT="A. Resources">
+<title>Preamble</title>
+<META NAME="description" CONTENT="Preamble">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" HREF="node41.html">
-<LINK REL="previous" HREF="node36.html">
-<LINK REL="up" HREF="zodb.html">
+<LINK REL="previous" HREF="node39.html">
+<LINK REL="up" HREF="node39.html">
 <LINK REL="next" HREF="node41.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node39.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node41.html"><img src="/python/writing/icons/next.gif"
@@ -40,36 +41,40 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node39.html">5.3 B-tree Modules</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node41.html">B..1 Applicability and Definitions</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H1><A NAME="SECTION000700000000000000000">
-A. Resources</A>
-</H1>
+<H2><A NAME="SECTION000810000000000000000">
+Preamble</A>
+</H2>
 
 <P>
-ZODB HOWTO, by Michel Pelletier:
+The purpose of this License is to make a manual, textbook, or other
+written document ``free'' in the sense of freedom: to assure everyone
+the effective freedom to copy and redistribute it, with or without
+modifying it, either commercially or noncommercially.  Secondarily,
+this License preserves for the author and publisher a way to get
+credit for their work, while not being considered responsible for
+modifications made by others.
 
-<BR>
-Goes into slightly more detail about the rules for writing applications using the ZODB.
-
-<BR><a class="url" href="http://www.zope.org/Members/michel/HowTos/ZODB-How-To">http://www.zope.org/Members/michel/HowTos/ZODB-How-To</a>
 <P>
-Introduction to the Zope Object Database, by Jim Fulton:
-
-<BR>
-Goes into much greater detail, explaining advanced uses of the ZODB and 
-how it's actually implemented.  A definitive reference, and highly recommended.
+This License is a kind of ``copyleft'', which means that derivative
+works of the document must themselves be free in the same sense.  It
+complements the GNU General Public License, which is a copyleft
+license designed for free software.
 
-<BR><a class="url" href="http://www.python.org/workshops/2000-01/proceedings/papers/fulton/zodb3.html">http://www.python.org/workshops/2000-01/proceedings/papers/fulton/zodb3.html</a>
-<P>
-Download link for ZEO: 
-<BR><a class="url" href="http://www.zope.org/Products/ZEO/">http://www.zope.org/Products/ZEO/</a>
 <P>
+We have designed this License in order to use it for manuals for free
+software, because free software needs free documentation: a free
+program should come with manuals providing the same freedoms that the
+software does.  But this License is not limited to software manuals;
+it can be used for any textual work, regardless of subject matter or
+whether it is published as a printed book.  We recommend this License
+principally for works whose purpose is instruction or reference.
 
 <P>
 
@@ -80,7 +85,7 @@ Download link for ZEO:
 <td><A HREF="node39.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node41.html"><img src="/python/writing/icons/next.gif"
@@ -97,11 +102,11 @@ Download link for ZEO:
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node39.html">5.3 B-tree Modules</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node41.html">B..1 Applicability and Definitions</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node41.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>B. GNU Free Documentation License</title>
-<META NAME="description" CONTENT="B. GNU Free Documentation License">
+<title>B..1 Applicability and Definitions</title>
+<META NAME="description" CONTENT="B..1 Applicability and Definitions">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
-<LINK REL="next" href="about.html">
+<LINK REL="next" HREF="node42.html">
 <LINK REL="previous" HREF="node40.html">
-<LINK REL="up" HREF="zodb.html">
+<LINK REL="up" HREF="node39.html">
 <LINK REL="next" HREF="node42.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node40.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node42.html"><img src="/python/writing/icons/next.gif"
@@ -40,52 +41,84 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node40.html">A. Resources</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node42.html">Preamble</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node40.html">Preamble</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node42.html">B..2 Verbatim Copying</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H1><A NAME="SECTION000800000000000000000">
-B. GNU Free Documentation License</A>
-</H1>
+<H2><A NAME="SECTION000820000000000000000">
+B..1 Applicability and Definitions</A>
+</H2>
 
 <P>
-Version 1.1, March 2000
-<BR>
+This License applies to any manual or other work that contains a
+notice placed by the copyright holder saying it can be distributed
+under the terms of this License.  The ``Document'', below, refers to any
+such manual or work.  Any member of the public is a licensee, and is
+addressed as ``you''.
+
 <P>
-Copyright <SPAN CLASS="MATH"><IMG
- WIDTH="20" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
- SRC="img1.gif"
- ALT="$\copyright$"></SPAN> 2000  Free Software Foundation, Inc.
-<BR>
-59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-<BR>
-Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
+A ``Modified Version'' of the Document means any work containing the
+Document or a portion of it, either copied verbatim, or with
+modifications and/or translated into another language.
 
 <P>
+A ``Secondary Section'' is a named appendix or a front-matter section of
+the Document that deals exclusively with the relationship of the
+publishers or authors of the Document to the Document's overall subject
+(or to related matters) and contains nothing that could fall directly
+within that overall subject.  (For example, if the Document is in part a
+textbook of mathematics, a Secondary Section may not explain any
+mathematics.)  The relationship could be a matter of historical
+connection with the subject or with related matters, or of legal,
+commercial, philosophical, ethical or political position regarding
+them.
 
-<p><hr>
-<!--Table of Child-Links-->
-<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
+<P>
+The ``Invariant Sections'' are certain Secondary Sections whose titles
+are designated, as being those of Invariant Sections, in the notice
+that says that the Document is released under this License.
 
-<UL>
-<LI><A href="node42.html">Preamble</a>
-<LI><A href="node43.html">B..1 Applicability and Definitions</a>
-<LI><A href="node44.html">B..2 Verbatim Copying</a>
-<LI><A href="node45.html">B..3 Copying in Quantity</a>
-<LI><A href="node46.html">B..4 Modifications</a>
-<LI><A href="node47.html">B..5 Combining Documents</a>
-<LI><A href="node48.html">B..6 Collections of Documents</a>
-<LI><A href="node49.html">B..7 Aggregation With Independent Works</a>
-<LI><A href="node50.html">B..8 Translation</a>
-<LI><A href="node51.html">B..9 Termination</a>
-<LI><A href="node52.html">B..10 Future Revisions of This Licence</a>
-<LI><A href="node53.html">ADDENDUM: How to use this License for your documents</a>
-</ul>
-<!--End of Table of Child-Links-->
+<P>
+The ``Cover Texts'' are certain short passages of text that are listed,
+as Front-Cover Texts or Back-Cover Texts, in the notice that says that
+the Document is released under this License.
+
+<P>
+A ``Transparent'' copy of the Document means a machine-readable copy,
+represented in a format whose specification is available to the
+general public, whose contents can be viewed and edited directly and
+straightforwardly with generic text editors or (for images composed of
+pixels) generic paint programs or (for drawings) some widely available
+drawing editor, and that is suitable for input to text formatters or
+for automatic translation to a variety of formats suitable for input
+to text formatters.  A copy made in an otherwise Transparent file
+format whose markup has been designed to thwart or discourage
+subsequent modification by readers is not Transparent.  A copy that is
+not ``Transparent'' is called ``Opaque''.
+
+<P>
+Examples of suitable formats for Transparent copies include plain
+ASCII without markup, Texinfo input format, <SPAN CLASS="logo,LaTeX">L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X</SPAN>&nbsp;input format, SGML
+or XML using a publicly available DTD, and standard-conforming simple
+HTML designed for human modification.  Opaque formats include
+PostScript, PDF, proprietary formats that can be read and edited only
+by proprietary word processors, SGML or XML for which the DTD and/or
+processing tools are not generally available, and the
+machine-generated HTML produced by some word processors for output
+purposes only.
+
+<P>
+The ``Title Page'' means, for a printed book, the title page itself,
+plus such following pages as are needed to hold, legibly, the material
+this License requires to appear in the title page.  For works in
+formats which do not have any title page as such, ``Title Page'' means
+the text near the most prominent appearance of the work's title,
+preceding the beginning of the body of the text.
+
+<P>
 
 <DIV CLASS="navigation">
 <p><hr>
@@ -94,7 +127,7 @@ Everyone is permitted to copy and distribute verbatim copies
 <td><A HREF="node40.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="zodb.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node42.html"><img src="/python/writing/icons/next.gif"
@@ -111,11 +144,11 @@ Everyone is permitted to copy and distribute verbatim copies
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node40.html">A. Resources</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="zodb.html">ZODB/ZEO Programming Guide</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node42.html">Preamble</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node40.html">Preamble</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node42.html">B..2 Verbatim Copying</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node42.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>Preamble</title>
-<META NAME="description" CONTENT="Preamble">
+<title>B..2 Verbatim Copying</title>
+<META NAME="description" CONTENT="B..2 Verbatim Copying">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" HREF="node43.html">
 <LINK REL="previous" HREF="node41.html">
-<LINK REL="up" HREF="node41.html">
+<LINK REL="up" HREF="node39.html">
 <LINK REL="next" HREF="node43.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node41.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node41.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node43.html"><img src="/python/writing/icons/next.gif"
@@ -40,40 +41,31 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node43.html">B..1 Applicability and Definitions</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node41.html">B..1 Applicability and Definitions</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node43.html">B..3 Copying in Quantity</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000810000000000000000">
-Preamble</A>
+<H2><A NAME="SECTION000830000000000000000">
+B..2 Verbatim Copying</A>
 </H2>
 
 <P>
-The purpose of this License is to make a manual, textbook, or other
-written document ``free'' in the sense of freedom: to assure everyone
-the effective freedom to copy and redistribute it, with or without
-modifying it, either commercially or noncommercially.  Secondarily,
-this License preserves for the author and publisher a way to get
-credit for their work, while not being considered responsible for
-modifications made by others.
+You may copy and distribute the Document in any medium, either
+commercially or noncommercially, provided that this License, the
+copyright notices, and the license notice saying this License applies
+to the Document are reproduced in all copies, and that you add no other
+conditions whatsoever to those of this License.  You may not use
+technical measures to obstruct or control the reading or further
+copying of the copies you make or distribute.  However, you may accept
+compensation in exchange for copies.  If you distribute a large enough
+number of copies you must also follow the conditions in section 3.
 
 <P>
-This License is a kind of ``copyleft'', which means that derivative
-works of the document must themselves be free in the same sense.  It
-complements the GNU General Public License, which is a copyleft
-license designed for free software.
-
-<P>
-We have designed this License in order to use it for manuals for free
-software, because free software needs free documentation: a free
-program should come with manuals providing the same freedoms that the
-software does.  But this License is not limited to software manuals;
-it can be used for any textual work, regardless of subject matter or
-whether it is published as a printed book.  We recommend this License
-principally for works whose purpose is instruction or reference.
+You may also lend copies, under the same conditions stated above, and
+you may publicly display copies.
 
 <P>
 
@@ -84,7 +76,7 @@ principally for works whose purpose is instruction or reference.
 <td><A HREF="node41.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node41.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node43.html"><img src="/python/writing/icons/next.gif"
@@ -101,11 +93,11 @@ principally for works whose purpose is instruction or reference.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node43.html">B..1 Applicability and Definitions</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node41.html">B..1 Applicability and Definitions</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node43.html">B..3 Copying in Quantity</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

doc/guide/zodb/node48.html

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html>
 <head>
-<title>B..6 Collections of Documents</title>
-<META NAME="description" CONTENT="B..6 Collections of Documents">
+<title>B..8 Translation</title>
+<META NAME="description" CONTENT="B..8 Translation">
 <META NAME="keywords" CONTENT="zodb">
 <META NAME="resource-type" CONTENT="document">
 <META NAME="distribution" CONTENT="global">
-<meta http-equiv="Content-Type" content="text/html; charset=">
-<link rel="STYLESHEET" href="zodb.css">
+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+<link rel="STYLESHEET" href="zodb.css" type='text/css'>
 <link rel="first" href="zodb.html">
 <link rel="contents" href="contents.html" title="Contents">
 
 <LINK REL="next" HREF="node49.html">
 <LINK REL="previous" HREF="node47.html">
-<LINK REL="up" HREF="node41.html">
+<LINK REL="up" HREF="node39.html">
 <LINK REL="next" HREF="node49.html">
+<meta name='aesop' content='information'>
 </head>
 <body>
 <DIV CLASS="navigation">
@@ -23,7 +24,7 @@
 <td><A HREF="node47.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node41.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node49.html"><img src="/python/writing/icons/next.gif"
@@ -40,29 +41,28 @@
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node47.html">B..5 Combining Documents</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node49.html">B..7 Aggregation With Independent</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node47.html">B..7 Aggregation With Independent</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node49.html">B..9 Termination</A>
 <br><hr>
 </DIV>
 <!--End of Navigation Panel-->
 
-<H2><A NAME="SECTION000870000000000000000">
-B..6 Collections of Documents</A>
+<H2><A NAME="SECTION000890000000000000000">
+B..8 Translation</A>
 </H2>
 
 <P>
-You may make a collection consisting of the Document and other documents
-released under this License, and replace the individual copies of this
-License in the various documents with a single copy that is included in
-the collection, provided that you follow the rules of this License for
-verbatim copying of each of the documents in all other respects.
-
-<P>
-You may extract a single document from such a collection, and distribute
-it individually under this License, provided you insert a copy of this
-License into the extracted document, and follow this License in all
-other respects regarding verbatim copying of that document.
+Translation is considered a kind of modification, so you may
+distribute translations of the Document under the terms of section 4.
+Replacing Invariant Sections with translations requires special
+permission from their copyright holders, but you may include
+translations of some or all Invariant Sections in addition to the
+original versions of these Invariant Sections.  You may include a
+translation of this License provided that you also include the
+original English version of this License.  In case of a disagreement
+between the translation and the original English version of this
+License, the original English version will prevail.
 
 <P>
 
@@ -73,7 +73,7 @@ other respects regarding verbatim copying of that document.
 <td><A HREF="node47.html"><img src="/python/writing/icons/previous.gif"
   border="0" height="32"
   alt="Previous Page" width="32"></A></td>
-<td><A HREF="node41.html"><img src="/python/writing/icons/up.gif"
+<td><A HREF="node39.html"><img src="/python/writing/icons/up.gif"
   border="0" height="32"
   alt="Up One Level" width="32"></A></td>
 <td><A HREF="node49.html"><img src="/python/writing/icons/next.gif"
@@ -90,11 +90,11 @@ other respects regarding verbatim copying of that document.
   border="0" height="32"
   alt="" width="32"></td>
 </tr></table>
-<b class="navlabel">Previous:</b> <a class="sectref" HREF="node47.html">B..5 Combining Documents</A>
-<b class="navlabel">Up:</b> <a class="sectref" HREF="node41.html">B. GNU Free Documentation</A>
-<b class="navlabel">Next:</b> <a class="sectref" HREF="node49.html">B..7 Aggregation With Independent</A>
+<b class="navlabel">Previous:</b> <a class="sectref" HREF="node47.html">B..7 Aggregation With Independent</A>
+<b class="navlabel">Up:</b> <a class="sectref" HREF="node39.html">B. GNU Free Documentation</A>
+<b class="navlabel">Next:</b> <a class="sectref" HREF="node49.html">B..9 Termination</A>
 <hr>
-<span class="release-info">Release 0.03, documentation updated on February 8, 2002.</span>
+<span class="release-info">Release 0.04, documentation updated on October 4, 2002.</span>
 </DIV>
 <!--End of Navigation Panel-->
 

src/ZEO/StorageServer.py

@@ -43,7 +43,7 @@ def set_label():
     """Internal helper to reset the logging label (e.g. after fork())."""
     global _label
     _label = "ZSS:%s" % os.getpid()
-    
+
 def log(message, level=zLOG.INFO, label=None, error=None):
     """Internal helper to log a message using zLOG."""
     zLOG.LOG(label or _label, level, message, error=error)

src/ZEO/version.txt

-2.0b1
+2.0b2