SAVEPOINTNameSAVEPOINT -- define a new savepoint within the current transaction SynopsisSAVEPOINT 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 to
rollback to a savepoint. Use RELEASE SAVEPOINT 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 table VALUES (1);
SAVEPOINT my_savepoint;
INSERT INTO table VALUES (2);
ROLLBACK TO SAVEPOINT my_savepoint;
INSERT INTO table 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 table VALUES (3);
SAVEPOINT my_savepoint;
INSERT INTO table 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
EnterpriseDB, 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.
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