Overview of Other Syntax

In addition to DCL, DDL, and DML syntax, M-compatible also provides syntax for other functions.

M compatibility provides statements for showing an execution plan of an SQL statement. For details, see EXPLAIN.

M compatibility provides statements for collecting statistics about the table content in the database. For details, see ANALYZE.

M compatibility provides statements for recycling storage space occupied by deleted rows in a table or B-Tree index. For details, see VACUUM.

M compatibility provides statements for creating a prepared statement. For details, see PREPARE.

**Table 1** SQL statements related to prepared statements
Function	SQL Statement
Executing a prepared statement	EXECUTE
Deallocating a prepared statement	DEALLOCATE and DROP PREPARE

**Table 2** SQL statements related to transactions
Function	SQL Statement
Rolling back the current transaction and canceling the changes in the transaction	ROLLBACK
Starting a transaction	BEGIN
	SET TRANSACTION
	START TRANSACTION
Preparing the current transaction for two-phase commit	PREPARE TRANSACTION
Committing the current transaction	COMMIT
Committing a prepared two-phase transaction	COMMIT PREPARED
Deleting a savepoint previously defined for the current transaction	RELEASE SAVEPOINT
Rolling back to a savepoint	ROLLBACK TO SAVEPOINT
Canceling a transaction ready for two-phase commit	ROLLBACK PREPARED
Creating a savepoint in the current transaction	SAVEPOINT
Setting a checkpoint	CHECKPOINT

**Table 3** SQL statements for modifying, displaying, and restoring a GUC parameter
Function	SQL Statement
Modifying a GUC parameter	SET
Showing the current value of a GUC parameter	SHOW
Restoring a GUC parameter to the default value	RESET

**Table 4** SQL statements for setting a user identifier
Function	SQL Statement
Setting the current user identifier of the current session	SET ROLE
Setting the session user identifier and the current user identifier of the current session to a specified user	SET SESSION AUTHORIZATION