SAVEPOINT()			 SQL Commands			   SAVEPOINT()



NAME
       SAVEPOINT - define a new savepoint within the current transaction


SYNOPSIS
       SAVEPOINT savepoint_name


DESCRIPTION
       SAVEPOINT establishes a new savepoint within the current transaction.

       A savepoint is a special mark inside a transaction that allows all com-
       mands that are executed after it was established	 to  be	 rolled	 back,
       restoring the transaction state to what it was at the time of the save-
       point.

PARAMETERS
       savepoint_name
	      The name to give to the new savepoint.

NOTES
       Use ROLLBACK TO SAVEPOINT [rollback_to_savepoint(7)] to rollback	 to  a
       savepoint.  Use	RELEASE	 SAVEPOINT [release_savepoint(7)] to destroy a
       savepoint, keeping the effects of commands executed after it was estab-
       lished.

       Savepoints  can	only  be  established when inside a transaction block.
       There can be multiple savepoints defined within a transaction.

EXAMPLES
       To establish a savepoint and later undo the  effects  of	 all  commands
       executed after it was established:

       BEGIN;
	   INSERT INTO table1 VALUES (1);
	   SAVEPOINT my_savepoint;
	   INSERT INTO table1 VALUES (2);
	   ROLLBACK TO SAVEPOINT my_savepoint;
	   INSERT INTO table1 VALUES (3);
       COMMIT;

       The above transaction will insert the values 1 and 3, but not 2.

       To establish and later destroy a savepoint:

       BEGIN;
	   INSERT INTO table1 VALUES (3);
	   SAVEPOINT my_savepoint;
	   INSERT INTO table1 VALUES (4);
	   RELEASE SAVEPOINT my_savepoint;
       COMMIT;

       The above transaction will insert both 3 and 4.

COMPATIBILITY
       SQL  requires  a	 savepoint  to be destroyed automatically when another
       savepoint with the same name is established.  In	 PostgreSQL,  the  old
       savepoint  is  kept,  though only the more recent one will be used when
       rolling back or releasing. (Releasing the newer	savepoint  will	 cause
       the  older  one to again become accessible to ROLLBACK TO SAVEPOINT and
       RELEASE SAVEPOINT.)  Otherwise, SAVEPOINT is fully SQL conforming.

SEE ALSO
       BEGIN [begin(7)], COMMIT [commit(l)], RELEASE SAVEPOINT	[release_save-
       point(l)],   ROLLBACK   [rollback(l)],  ROLLBACK	 TO  SAVEPOINT	[roll-
       back_to_savepoint(l)]



SQL - Language Statements	  2010-12-14			   SAVEPOINT()