MDEV-7286 TRIGGER: CREATE OR REPLACE, CREATE IF NOT EXISTS

Based on the patch by Sriram Patil, made under terms of GSoC 2014.

mysql-test/r/create.result

@@ -2120,6 +2120,11 @@ CREATE TRIGGER f BEFORE INSERT ON t1 FOR EACH ROW
 BEGIN 
 UPDATE A SET `pk`=1 WHERE `pk`=0 ; 
 END ;|
+ERROR HY000: Trigger already exists
+CREATE TRIGGER f1 BEFORE INSERT ON t1 FOR EACH ROW 
+BEGIN 
+UPDATE A SET `pk`=1 WHERE `pk`=0 ; 
+END ;|
 ERROR 42000: This version of MariaDB doesn't yet support 'multiple triggers with the same action time and event for one table'
 DROP TABLE t1;
 DROP TABLE B;

mysql-test/r/create_drop_binlog.result

@@ -267,3 +267,40 @@ Log_name	Pos	Event_type	Server_id	End_log_pos	Info
 #	#	Gtid	1	#	GTID #-#-#
 #	#	Query	1	#	use `test`; DROP EVENT IF EXISTS ev1
 RESET MASTER;
+CREATE TABLE t1 (a INT);
+CREATE OR REPLACE TRIGGER tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=10;
+CREATE OR REPLACE TRIGGER tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=11;
+DROP TRIGGER tr1;
+CREATE TRIGGER IF NOT EXISTS tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=20;
+CREATE TRIGGER IF NOT EXISTS tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=21;
+Warnings:
+Note	1359	Trigger already exists
+DROP TRIGGER IF EXISTS tr1;
+DROP TRIGGER IF EXISTS tr1;
+Warnings:
+Note	1360	Trigger does not exist
+DROP TABLE t1;
+SHOW BINLOG EVENTS;
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+#	#	Format_desc	1	#	VER
+#	#	Gtid_list	1	#	[]
+#	#	Binlog_checkpoint	1	#	master-bin.000001
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; CREATE TABLE t1 (a INT)
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; CREATE OR REPLACE DEFINER=`root`@`localhost` TRIGGER tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=10
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; CREATE OR REPLACE DEFINER=`root`@`localhost` TRIGGER tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=11
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; DROP TRIGGER tr1
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; CREATE DEFINER=`root`@`localhost` TRIGGER IF NOT EXISTS tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=20
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; CREATE DEFINER=`root`@`localhost` TRIGGER IF NOT EXISTS tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=21
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; DROP TRIGGER IF EXISTS tr1
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; DROP TRIGGER IF EXISTS tr1
+#	#	Gtid	1	#	GTID #-#-#
+#	#	Query	1	#	use `test`; DROP TABLE `t1` /* generated by server */
+RESET MASTER;

mysql-test/r/create_drop_trigger.result

+CREATE DATABASE db1;
+USE db1;
+CREATE TABLE t1 (val INT);
+CREATE TRIGGER IF NOT EXISTS val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val;
+SET @sum=0;
+INSERT INTO t1 VALUES (10), (20), (30);
+SELECT @sum;
+@sum
+60
+CREATE TRIGGER IF NOT EXISTS val_sum_new BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val;
+ERROR 42000: This version of MariaDB doesn't yet support 'multiple triggers with the same action time and event for one table'
+CREATE TRIGGER IF NOT EXISTS val_sum AFTER INSERT ON t1 FOR EACH ROW SET @sum = @sum + 1 + NEW.val;
+Warnings:
+Note	1359	Trigger already exists
+CREATE OR REPLACE TRIGGER IF NOT EXISTS val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 2 + NEW.val;
+ERROR HY000: Incorrect usage of OR REPLACE and IF NOT EXISTS
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT
+SET @sum = @sum + NEW.val
+CREATE OR REPLACE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 3 + NEW.val;
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT
+SET @sum = @sum + 3 + NEW.val
+CREATE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 4 + NEW.val;
+ERROR HY000: Trigger already exists
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT
+SET @sum = @sum + 3 + NEW.val
+# Clearing up
+DROP TRIGGER IF EXISTS val_sum;
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT
+DROP TRIGGER IF EXISTS val_sum;
+Warnings:
+Note	1360	Trigger does not exist
+DROP TABLE t1;
+DROP DATABASE db1;

mysql-test/r/create_or_replace.result

@@ -6,8 +6,6 @@ INSERT INTO t2 VALUES(1),(2),(3);
 #
 CREATE OR REPLACE TABLE IF NOT EXISTS t1 (a int);
 ERROR HY000: Incorrect usage of OR REPLACE and IF NOT EXISTS
-create or replace trigger trg before insert on t1 for each row set @a:=1;
-ERROR HY000: Incorrect usage of OR REPLACE and TRIGGERS / SP / EVENT
 create or replace table mysql.general_log (a int);
 ERROR HY000: You cannot 'CREATE OR REPLACE' a log table if logging is enabled
 create or replace table mysql.slow_log (a int);

mysql-test/r/trigger.result

@@ -1957,6 +1957,8 @@ drop table if exists t1;
 create table t1 (i int, j int);
 create trigger t1_bi before insert on t1 for each row begin end;
 create trigger t1_bi before insert on t1 for each row begin end;
+ERROR HY000: Trigger already exists
+create trigger t1_bi2 before insert on t1 for each row begin end;
 ERROR 42000: This version of MariaDB doesn't yet support 'multiple triggers with the same action time and event for one table'
 drop trigger t1_bi;
 drop trigger t1_bi;

mysql-test/suite/rpl/r/rpl_create_drop_trigger.result

+include/master-slave.inc
+[connection master]
+# Part 1 - initial creation
+CREATE DATABASE db1;
+USE db1;
+CREATE TABLE t1 (val INT);
+CREATE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val + 1;
+SET @sum=0;
+INSERT INTO t1 VALUES (10), (20), (30);
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Master FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT_Master
+SET @sum = @sum + NEW.val + 1
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Slave FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT_Slave
+SET @sum = @sum + NEW.val + 1
+# Part 2 - CREATE IF NOT EXISTS (on a existing trigger)
+CREATE TRIGGER IF NOT EXISTS val_sum AFTER INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val + 2;
+Warnings:
+Note	1359	Trigger already exists
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Master FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT_Master
+SET @sum = @sum + NEW.val + 1
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Slave FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT_Slave
+SET @sum = @sum + NEW.val + 1
+# Part 3 - CREATE OR REPLACE (on a existing trigger)
+CREATE OR REPLACE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val + 3;
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Master FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT_Master
+SET @sum = @sum + NEW.val + 3
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Slave FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+ACTION_STATEMENT_Slave
+SET @sum = @sum + NEW.val + 3
+# Clearing up
+DROP TRIGGER val_sum;
+DROP TABLE t1;
+DROP TRIGGER IF EXISTS val_sum;
+Warnings:
+Note	1360	Trigger does not exist
+DROP TRIGGER random_trigger;
+ERROR HY000: Trigger does not exist
+DROP DATABASE db1;
+DROP TRIGGER IF EXISTS val_sum;
+ERROR 3D000: No database selected
+# Syncing slave with master
+DROP TRIGGER val_sum;
+ERROR HY000: Trigger does not exist
+include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_create_drop_trigger.test

+--source include/master-slave.inc
+
+--echo # Part 1 - initial creation
+connection master;
+CREATE DATABASE db1;
+USE db1;
+CREATE TABLE t1 (val INT);
+CREATE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val + 1;
+SET @sum=0;
+INSERT INTO t1 VALUES (10), (20), (30);
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Master FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+sync_slave_with_master;
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Slave FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+
+--echo # Part 2 - CREATE IF NOT EXISTS (on a existing trigger)
+connection master;
+CREATE TRIGGER IF NOT EXISTS val_sum AFTER INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val + 2;
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Master FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+sync_slave_with_master;
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Slave FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+
+--echo # Part 3 - CREATE OR REPLACE (on a existing trigger)
+connection master;
+CREATE OR REPLACE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val + 3;
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Master FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+sync_slave_with_master;
+SELECT ACTION_STATEMENT AS ACTION_STATEMENT_Slave FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+
+--echo # Clearing up
+connection master;
+DROP TRIGGER val_sum;
+DROP TABLE t1;
+DROP TRIGGER IF EXISTS val_sum;
+
+--error ER_TRG_DOES_NOT_EXIST
+DROP TRIGGER random_trigger;
+DROP DATABASE db1;
+
+--error ER_NO_DB_ERROR
+DROP TRIGGER IF EXISTS val_sum;
+
+--echo # Syncing slave with master
+sync_slave_with_master;
+
+--error ER_TRG_DOES_NOT_EXIST
+DROP TRIGGER val_sum;
+
+--source include/rpl_end.inc

mysql-test/t/create.test

@@ -1622,12 +1622,18 @@ END ; |
 INSERT INTO t1 (pk, int_key) SELECT `pk` , `int_key` FROM B ;
 
 --delimiter |
---error ER_NOT_SUPPORTED_YET
+--error ER_TRG_ALREADY_EXISTS
 CREATE TRIGGER f BEFORE INSERT ON t1 FOR EACH ROW 
 BEGIN 
   UPDATE A SET `pk`=1 WHERE `pk`=0 ; 
 END ;|
 
+--error ER_NOT_SUPPORTED_YET
+CREATE TRIGGER f1 BEFORE INSERT ON t1 FOR EACH ROW 
+BEGIN 
+  UPDATE A SET `pk`=1 WHERE `pk`=0 ; 
+END ;|
+
 --delimiter ;
 
 DROP TABLE t1;

mysql-test/t/create_drop_binlog.test

@@ -127,6 +127,22 @@ CREATE OR REPLACE EVENT ev1 ON SCHEDULE EVERY 1 SECOND DO DROP TABLE IF EXISTS t
 SELECT EVENT_NAME, EVENT_DEFINITION FROM INFORMATION_SCHEMA.EVENTS;
 DROP EVENT ev1;
 DROP EVENT IF EXISTS ev1;
+
+--replace_column 1 # 2 # 5 #
+--replace_regex /xid=[0-9]+/xid=XX/ /GTID [0-9]+-[0-9]+-[0-9]+/GTID #-#-#/ /Server.ver.*/VER/
+SHOW BINLOG EVENTS;
+RESET MASTER;
+
+CREATE TABLE t1 (a INT);
+CREATE OR REPLACE TRIGGER tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=10;
+CREATE OR REPLACE TRIGGER tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=11;
+DROP TRIGGER tr1;
+CREATE TRIGGER IF NOT EXISTS tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=20;
+CREATE TRIGGER IF NOT EXISTS tr1 BEFORE INSERT ON t1 FOR EACH ROW SET NEW.a=21;
+DROP TRIGGER IF EXISTS tr1;
+DROP TRIGGER IF EXISTS tr1;
+DROP TABLE t1;
+
 --replace_column 1 # 2 # 5 #
 --replace_regex /xid=[0-9]+/xid=XX/ /GTID [0-9]+-[0-9]+-[0-9]+/GTID #-#-#/ /Server.ver.*/VER/
 SHOW BINLOG EVENTS;

mysql-test/t/create_drop_trigger.test

+CREATE DATABASE db1;
+USE db1;
+CREATE TABLE t1 (val INT);
+CREATE TRIGGER IF NOT EXISTS val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val;
+SET @sum=0;
+INSERT INTO t1 VALUES (10), (20), (30);
+SELECT @sum;
+
+--error ER_NOT_SUPPORTED_YET
+CREATE TRIGGER IF NOT EXISTS val_sum_new BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + NEW.val;
+
+CREATE TRIGGER IF NOT EXISTS val_sum AFTER INSERT ON t1 FOR EACH ROW SET @sum = @sum + 1 + NEW.val;
+
+--error ER_WRONG_USAGE
+CREATE OR REPLACE TRIGGER IF NOT EXISTS val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 2 + NEW.val;
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+
+CREATE OR REPLACE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 3 + NEW.val;
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+
+--error ER_TRG_ALREADY_EXISTS
+CREATE TRIGGER val_sum BEFORE INSERT ON t1 FOR EACH ROW SET @sum = @sum + 4 + NEW.val;
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+
+--echo # Clearing up
+DROP TRIGGER IF EXISTS val_sum;
+SELECT ACTION_STATEMENT FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_NAME='val_sum';
+DROP TRIGGER IF EXISTS val_sum;
+
+DROP TABLE t1;
+DROP DATABASE db1;

mysql-test/t/create_or_replace.test

@@ -21,8 +21,6 @@ INSERT INTO t2 VALUES(1),(2),(3);
 
 --error ER_WRONG_USAGE
 CREATE OR REPLACE TABLE IF NOT EXISTS t1 (a int);
---error ER_WRONG_USAGE
-create or replace trigger trg before insert on t1 for each row set @a:=1;
 
 # check that we don't try to create a log table in use
 --error ER_BAD_LOG_STATEMENT

mysql-test/t/trigger.test

@@ -2237,8 +2237,10 @@ drop table if exists t1;
 create table t1 (i int, j int);
 
 create trigger t1_bi before insert on t1 for each row begin end;
---error ER_NOT_SUPPORTED_YET
+--error ER_TRG_ALREADY_EXISTS
 create trigger t1_bi before insert on t1 for each row begin end;
+--error ER_NOT_SUPPORTED_YET
+create trigger t1_bi2 before insert on t1 for each row begin end;
 drop trigger t1_bi;
 --error ER_TRG_DOES_NOT_EXIST
 drop trigger t1_bi;

sql/sql_trigger.cc

@@ -608,6 +608,63 @@ end:
   DBUG_RETURN(result);
 }
 
+/**
+  Build stmt_query to write it in the bin-log
+  and get the trigger definer.
+
+  @param thd           current thread context (including trigger definition in
+                       LEX)
+  @param tables        table list containing one open table for which the
+                       trigger is created.
+  @param[out] stmt_query    after successful return, this string contains
+                            well-formed statement for creation this trigger.
+
+  @param[out] trg_definer         The triggger definer.
+  @param[out] trg_definer_holder  Used as a buffer for definer.
+
+  @note
+    - Assumes that trigger name is fully qualified.
+    - NULL-string means the following LEX_STRING instance:
+    { str = 0; length = 0 }.
+    - In other words, definer_user and definer_host should contain
+    simultaneously NULL-strings (non-SUID/old trigger) or valid strings
+    (SUID/new trigger).
+*/
+static void build_trig_stmt_query(THD *thd, TABLE_LIST *tables,
+                                  String *stmt_query,
+                                  LEX_STRING *trg_definer,
+                                  char trg_definer_holder[])
+{
+  LEX *lex= thd->lex;
+
+  /*
+    Create a query with the full trigger definition.
+    The original query is not appropriate, as it can miss the DEFINER=XXX part.
+  */
+  stmt_query->append(STRING_WITH_LEN("CREATE "));
+
+  if (lex->create_info.or_replace())
+    stmt_query->append(STRING_WITH_LEN("OR REPLACE "));
+
+  if (lex->sphead->m_chistics->suid != SP_IS_NOT_SUID)
+  {
+    /* SUID trigger */
+    lex->definer->set_lex_string(trg_definer, trg_definer_holder);
+    append_definer(thd, stmt_query, &lex->definer->user, &lex->definer->host);
+  }
+  else
+  {
+    *trg_definer= empty_lex_str;
+  }
+
+  LEX_STRING stmt_definition;
+  stmt_definition.str= (char*) thd->lex->stmt_definition_begin;
+  stmt_definition.length= thd->lex->stmt_definition_end -
+                          thd->lex->stmt_definition_begin;
+  trim_whitespace(thd->charset(), &stmt_definition);
+  stmt_query->append(stmt_definition.str, stmt_definition.length);
+}
+
 
 /**
   Create trigger for table.
@@ -640,8 +697,6 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
   char file_buff[FN_REFLEN], trigname_buff[FN_REFLEN];
   LEX_STRING file, trigname_file;
   LEX_STRING *trg_def;
-  LEX_STRING definer_user;
-  LEX_STRING definer_host;
   ulonglong *trg_sql_mode;
   char trg_definer_holder[USER_HOST_BUFF_SIZE];
   LEX_STRING *trg_definer;
@@ -650,6 +705,8 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
   LEX_STRING *trg_client_cs_name;
   LEX_STRING *trg_connection_cl_name;
   LEX_STRING *trg_db_cl_name;
+  sp_head *trg_body= bodies[lex->trg_chistics.event]
+                           [lex->trg_chistics.action_time];
 
   if (check_for_broken_triggers())
     return true;
@@ -659,20 +716,31 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
                     lex->spname->m_db.str))
   {
     my_error(ER_TRG_IN_WRONG_SCHEMA, MYF(0));
-    return 1;
+    return true;
   }
 
-  /* We don't allow creation of several triggers of the same type yet */
-  if (bodies[lex->trg_chistics.event][lex->trg_chistics.action_time] != 0)
+  /*
+    We don't allow creation of several triggers of the same type yet.
+    If a trigger with the same type already exists:
+    a. Throw a ER_NOT_SUPPORTED_YET error,
+       if the old and the new trigger names are different;     
+    b. Or continue, if the old and the new trigger names are the same:
+       - either to recreate the trigger on "CREATE OR REPLACE"
+       - or send a "already exists" warning on "CREATE IF NOT EXISTS"
+       - or send an "alredy exists" error on normal CREATE.
+  */
+  if (trg_body != 0 &&
+      my_strcasecmp(table_alias_charset,
+                    trg_body->m_name.str, lex->spname->m_name.str))
   {
     my_error(ER_NOT_SUPPORTED_YET, MYF(0),
              "multiple triggers with the same action time"
              " and event for one table");
-    return 1;
+    return true;
   }
 
   if (sp_process_definer(thd))
-    return 1;
+    return true;
 
   /*
     Let us check if all references to fields in old/new versions of row in
@@ -701,7 +769,7 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
 
     if (!trg_field->fixed &&
         trg_field->fix_fields(thd, (Item **)0))
-      return 1;
+      return true;
   }
 
   /*
@@ -722,16 +790,37 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
   /* Use the filesystem to enforce trigger namespace constraints. */
   if (!access(trigname_buff, F_OK))
   {
-    my_error(ER_TRG_ALREADY_EXISTS, MYF(0));
+    if (lex->create_info.or_replace())
+    {
+      String drop_trg_query;
+      drop_trg_query.append("DROP TRIGGER ");
+      drop_trg_query.append(lex->spname->m_name.str);
+      if (drop_trigger(thd, tables, &drop_trg_query))
         return 1;
     }
+    else if (lex->create_info.if_not_exists())
+    {
+      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+                          ER_TRG_ALREADY_EXISTS, ER(ER_TRG_ALREADY_EXISTS),
+                          trigname_buff);
+      LEX_STRING trg_definer_tmp;
+      build_trig_stmt_query(thd, tables, stmt_query,
+                            &trg_definer_tmp, trg_definer_holder);
+      return false;
+    }
+    else
+    {
+      my_error(ER_TRG_ALREADY_EXISTS, MYF(0));
+      return true;
+    }
+  }
 
   trigname.trigger_table.str= tables->table_name;
   trigname.trigger_table.length= tables->table_name_length;
 
   if (sql_create_definition_file(NULL, &trigname_file, &trigname_file_type,
                                  (uchar*)&trigname, trigname_file_parameters))
-    return 1;
+    return true;
 
   /*
     Soon we will invalidate table object and thus Table_triggers_list object
@@ -764,29 +853,6 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
 
   *trg_sql_mode= thd->variables.sql_mode;
 
-  if (lex->sphead->m_chistics->suid != SP_IS_NOT_SUID)
-  {
-    /* SUID trigger. */
-
-    definer_user= lex->definer->user;
-    definer_host= lex->definer->host;
-
-    lex->definer->set_lex_string(trg_definer, trg_definer_holder);
-  }
-  else
-  {
-    /* non-SUID trigger. */
-
-    definer_user.str= 0;
-    definer_user.length= 0;
-
-    definer_host.str= 0;
-    definer_host.length= 0;
-
-    trg_definer->str= (char*) "";
-    trg_definer->length= 0;
-  }
-
   /*
     Fill character set information:
       - client character set contains charset info only;
@@ -802,30 +868,8 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
   lex_string_set(trg_db_cl_name,
                  get_default_db_collation(thd, tables->db)->name);
 
-  /*
-    Create well-formed trigger definition query. Original query is not
-    appropriated, because definer-clause can be not truncated.
-  */
-
-  stmt_query->append(STRING_WITH_LEN("CREATE "));
-
-  if (lex->sphead->m_chistics->suid != SP_IS_NOT_SUID)
-  {
-    /*
-      Append definer-clause if the trigger is SUID (a usual trigger in
-      new MySQL versions).
-    */
-
-    append_definer(thd, stmt_query, &definer_user, &definer_host);
-  }
-
-  LEX_STRING stmt_definition;
-  stmt_definition.str= (char*) thd->lex->stmt_definition_begin;
-  stmt_definition.length= thd->lex->stmt_definition_end
-    - thd->lex->stmt_definition_begin;
-  trim_whitespace(thd->charset(), & stmt_definition);
-
-  stmt_query->append(stmt_definition.str, stmt_definition.length);
+  build_trig_stmt_query(thd, tables, stmt_query,
+                        trg_definer, trg_definer_holder);
 
   trg_def->str= stmt_query->c_ptr_safe();
   trg_def->length= stmt_query->length();
@@ -834,11 +878,11 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
 
   if (!sql_create_definition_file(NULL, &file, &triggers_file_type,
                                   (uchar*)this, triggers_file_parameters))
-    return 0;
+    return false;
 
 err_with_cleanup:
   mysql_file_delete(key_file_trn, trigname_buff, MYF(MY_WME));
-  return 1;
+  return true;
 }
 
 

sql/sql_yacc.yy

@@ -2560,20 +2560,6 @@ create:
             Lex->create_view_suid= TRUE;
           }
           view_or_trigger_or_sp_or_event
-          {
-            // TODO: remove this when "MDEV-5359 CREATE OR REPLACE..." is done
-            if ($1.or_replace() &&
-                Lex->sql_command != SQLCOM_CREATE_EVENT &&
-                Lex->sql_command != SQLCOM_CREATE_VIEW &&
-                Lex->sql_command != SQLCOM_CREATE_FUNCTION &&
-                Lex->sql_command != SQLCOM_CREATE_SPFUNCTION &&
-                Lex->sql_command != SQLCOM_CREATE_PROCEDURE)
-            {
-               my_error(ER_WRONG_USAGE, MYF(0), "OR REPLACE",
-                       "TRIGGERS / SP / EVENT");
-               MYSQL_YYABORT;
-            }
-          }
         | create_or_replace USER opt_if_not_exists clear_privileges grant_list
           {
             if (Lex->set_command_with_check(SQLCOM_CREATE_USER, $1 | $3))
@@ -16159,23 +16145,28 @@ view_check_option:
 trigger_tail:
           TRIGGER_SYM
           remember_name
+          opt_if_not_exists
+          {
+            if (Lex->add_create_options_with_check($3))
+              MYSQL_YYABORT;
+          }
           sp_name
           trg_action_time
           trg_event
           ON
-          remember_name /* $7 */
-          { /* $8 */
+          remember_name /* $9 */
+          { /* $10 */
             Lex->raw_trg_on_table_name_begin= YYLIP->get_tok_start();
           }
-          table_ident /* $9 */
+          table_ident /* $11 */
           FOR_SYM
-          remember_name /* $11 */
-          { /* $12 */
+          remember_name /* $13 */
+          { /* $14 */
             Lex->raw_trg_on_table_name_end= YYLIP->get_tok_start();
           }
           EACH_SYM
           ROW_SYM
-          { /* $15 */
+          { /* $17 */
             LEX *lex= thd->lex;
             Lex_input_stream *lip= YYLIP;
 
@@ -16186,17 +16177,17 @@ trigger_tail:
             }
 
             lex->stmt_definition_begin= $2;
-            lex->ident.str= $7;
-            lex->ident.length= $11 - $7;
-            lex->spname= $3;
+            lex->ident.str= $9;
+            lex->ident.length= $13 - $9;
+            lex->spname= $5;
 
-            if (!make_sp_head(thd, $3, TYPE_ENUM_TRIGGER))
+            if (!make_sp_head(thd, $5, TYPE_ENUM_TRIGGER))
               MYSQL_YYABORT;
 
             lex->sphead->set_body_start(thd, lip->get_cpp_ptr());
           }
-          sp_proc_stmt /* $16 */
-          { /* $17 */
+          sp_proc_stmt /* $18 */
+          { /* $19 */
             LEX *lex= Lex;
             sp_head *sp= lex->sphead;
 
@@ -16212,7 +16203,7 @@ trigger_tail:
               sp_proc_stmt alternatives are not saving/restoring LEX, so
               lex->query_tables can be wiped out.
             */
-            if (!lex->select_lex.add_table_to_list(thd, $9,
+            if (!lex->select_lex.add_table_to_list(thd, $11,
                                                    (LEX_STRING*) 0,
                                                    TL_OPTION_UPDATING,
                                                    TL_READ_NO_INSERT,