linux man page for savepoint

SAVEPOINT(7)                                                       SQL Commands                                                       SAVEPOINT(7)

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 commands that are executed after it was established to be rolled back,
       restoring the transaction state to what it was at the time of the savepoint.

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 established.

       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(7)],  RELEASE  SAVEPOINT  [release_savepoint(7)],  ROLLBACK [rollback(7)], ROLLBACK TO SAVEPOINT [roll-
       back_to_savepoint(7)]

SQL - Language Statements                                           2010-05-14                                                        SAVEPOINT(7)