Introduce OneValue helper.

README

 Yet another SQLite binding based on:
  - original [Russ Cox's](http://code.google.com/p/gosqlite/) implementation,
  - the [Patrick Crosby's](https://github.com/patrickxb/fgosqlite/) fork.
+This binding implements the "exp/sql/driver" interface but leaves dangling statements (see drivert_test).
 
 Open supports flags.
 Conn#Exec handles multiple statements (separated by semicolons) properly.
@@ -8,9 +9,10 @@ Conn#Prepare can optionnaly #Bind as well.
 Conn#Close ensures that all dangling statements are finalized.
 Stmt#Exec is renamed in Stmt#Bind and a new Stmt#Exec method is introduced to #Bind and #Step.
 Stmt#Bind uses native sqlite3_bind_x methods and failed if unsupported type.
+Stmt#NamedBind can be used to bind by name.
 Stmt#Next returns a (bool, os.Error) couple like Reader#Read.
 Stmt#Scan uses native sqlite3_column_x methods.
-Stmt#NamedScan is added. It's compliant with [go-dbi](https://github.com/thomaslee/go-dbi/) API but I think its signature should be improved/modified.
+Stmt#NamedScan is added. It's compliant with [go-dbi](https://github.com/thomaslee/go-dbi/).
 Stmt#ScanByIndex/ScanByName are added to test NULL value.
 
 Currently, the weak point of the binding is the *Scan methods:
@@ -26,6 +28,10 @@ Using the native sqlite3_column_x implies:
 Maybe we should let the caller do the conversion.
 
 Misc:
+Conn#Exists
+Conn#OneValue
+
+Conn#OpenVfs
 Conn#EnableFkey/IsFKeyEnabled
 Conn#Changes/TotalChanges
 Conn#LastInsertRowid
@@ -33,8 +39,9 @@ Conn#Interrupt
 Conn#Begin/BeginTransaction(type)/Commit/Rollback
 Conn#GetAutocommit
 Conn#EnableLoadExtension/LoadExtension
+Conn#IntegrityCheck
 
-Stmt#ExecUpdate
+Stmt#ExecInsert/ExecUpdate
 Stmt#BindParameterCount/BindParameterIndex/BindParameterName
 Stmt#ClearBindings
 Stmt#ColumnCount/ColumnNames/ColumnIndex(name)/ColumnName(index)/ColumnType(index)
@@ -64,3 +71,8 @@ Conn#ProgressHandler
 Conn#SetAuthorizer
 Conn#Trace
 Stmt#Status
+
+Hook:
+Conn#CommitHook
+Conn#RollbackHook
+Conn#UpdateHook

function_test.go

@@ -24,22 +24,12 @@ func TestScalarFunction(t *testing.T) {
 	if err = db.CreateScalarFunction("half", 1, nil, half, nil); err != nil {
 		t.Fatalf("couldn't create function: %s", err)
 	}
-	s, err := db.Prepare("select half(6)")
+	d, err := db.OneValue("select half(6)")
 	if err != nil {
-		t.Fatalf("couldn't prepare statement: %s", err)
-	}
-	if b := Must(s.Next()); !b {
-		t.Fatalf("No result")
-	}
-	d, _, err := s.ScanDouble(0)
-	if err != nil {
-		t.Fatalf("couldn't scan result: %s", err)
-	}
-	if d != 3 {
-		t.Errorf("Expected %f but got %f", 3, d)
+		t.Fatalf("couldn't retrieve result: %s", err)
 	}
-	if err = s.Finalize(); err != nil {
-		t.Fatalf("couldn't finalize statement: %s", err)
+	if d != 3.0 {
+		t.Errorf("Expected %f but got %f", 3.0, d)
 	}
 	if err = db.CreateScalarFunction("half", 1, nil, nil, nil); err != nil {
 		t.Errorf("couldn't destroy function: %s", err)

sqlite.go

@@ -37,6 +37,7 @@ import "C"
 import (
 	"errors"
 	"fmt"
+	"io"
 	"reflect"
 	"unsafe"
 )
@@ -373,6 +374,23 @@ func (c *Conn) Exists(query string, args ...interface{}) (bool, error) {
 	return s.Next()
 }
 
+// Use it with SELECT that returns only one row with only one column.
+// Returns io.EOF when there is no row.
+func (c *Conn) OneValue(query string, args ...interface{}) (interface{}, error) {
+	s, err := c.Prepare(query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer s.Finalize()
+	b, err := s.Next()
+	if err != nil {
+		return nil, err
+	} else if !b {
+		return nil, io.EOF
+	}
+	return s.ScanValue(0), nil
+}
+
 // Count the number of rows modified
 // Calls http://sqlite.org/c3ref/changes.html
 func (c *Conn) Changes() int {
@@ -872,6 +890,7 @@ func (s *Stmt) ScanByName(name string, value interface{}) (bool, error) {
 
 // The leftmost column/index is number 0.
 //
+// Destination type is specified by the caller.
 // The value must be of one of the following types:
 //    *string
 //    *int, *int64, *byte,
@@ -912,7 +931,8 @@ func (s *Stmt) ScanByIndex(index int, value interface{}) (bool, error) {
 }
 
 // The leftmost column/index is number 0.
-// 
+//
+// Destination type is decided by SQLite.
 // The returned value will be of one of the following types:
 //    nil
 //    string
@@ -1193,20 +1213,10 @@ func (c *Conn) IntegrityCheck(max int, quick bool) error {
 	} else {
 		pragma = "integrity"
 	}
-	s, err := c.Prepare(fmt.Sprintf("PRAGMA %s_check(%d)", pragma, max))
+	msg, err := c.OneValue(fmt.Sprintf("PRAGMA %s_check(%d)", pragma, max))
 	if err != nil {
 		return err
 	}
-	defer s.Finalize()
-	if ok, err := s.Next(); err != nil {
-		return err
-	} else if !ok {
-		return c.specificError("Integrity check failed (no result)")
-	}
-	msg, null := s.ScanText(0)
-	if null {
-		return c.specificError("Integrity check failed (null result)")
-	}
 	if msg != "ok" {
 		return c.specificError("Integrity check failed (%s)", msg)
 	}

sqlite_test.go

@@ -166,7 +166,7 @@ func TestInsertWithStatement(t *testing.T) {
 	defer s.Finalize()
 
 	if s.ReadOnly() {
-		t.Errorf("update statement is not readonly")
+		t.Errorf("update statement should not be readonly")
 	}
 
 	paramCount := s.BindParameterCount()
@@ -200,7 +200,7 @@ func TestInsertWithStatement(t *testing.T) {
 	cs, _ := db.Prepare("SELECT COUNT(*) FROM test")
 	defer cs.Finalize()
 	if !cs.ReadOnly() {
-		t.Errorf("update statement is not readonly")
+		t.Errorf("select statement should be readonly")
 	}
 	if !Must(cs.Next()) {
 		t.Fatal("no result for count")