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savepoint(7) [freebsd man page]

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)

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ROLLBACK TO 
SAVEPOINT(7) SQL Commands ROLLBACK TO SAVEPOINT(7) NAME
ROLLBACK TO SAVEPOINT - roll back to a savepoint SYNOPSIS
ROLLBACK [ WORK | TRANSACTION ] TO [ SAVEPOINT ] savepoint_name DESCRIPTION
Roll back all commands that were executed after the savepoint was established. The savepoint remains valid and can be rolled back to again later, if needed. ROLLBACK TO SAVEPOINT implicitly destroys all savepoints that were established after the named savepoint. PARAMETERS
savepoint_name The savepoint to roll back to. NOTES
Use RELEASE SAVEPOINT [release_savepoint(7)] to destroy a savepoint without discarding the effects of commands executed after it was estab- lished. Specifying a savepoint name that has not been established is an error. Cursors have somewhat non-transactional behavior with respect to savepoints. Any cursor that is opened inside a savepoint will be closed when the savepoint is rolled back. If a previously opened cursor is affected by a FETCH command inside a savepoint that is later rolled back, the cursor position remains at the position that FETCH left it pointing to (that is, FETCH is not rolled back). Closing a cursor is not undone by rolling back, either. A cursor whose execution causes a transaction to abort is put in a cannot-execute state, so while the transaction can be restored using ROLLBACK TO SAVEPOINT, the cursor can no longer be used. EXAMPLES
To undo the effects of the commands executed after my_savepoint was established: ROLLBACK TO SAVEPOINT my_savepoint; Cursor positions are not affected by savepoint rollback: BEGIN; DECLARE foo CURSOR FOR SELECT 1 UNION SELECT 2; SAVEPOINT foo; FETCH 1 FROM foo; ?column? ---------- 1 ROLLBACK TO SAVEPOINT foo; FETCH 1 FROM foo; ?column? ---------- 2 COMMIT; COMPATIBILITY
The SQL standard specifies that the key word SAVEPOINT is mandatory, but PostgreSQL and Oracle allow it to be omitted. SQL allows only WORK, not TRANSACTION, as a noise word after ROLLBACK. Also, SQL has an optional clause AND [ NO ] CHAIN which is not currently supported by PostgreSQL. Otherwise, this command conforms to the SQL standard. SEE ALSO
BEGIN [begin(7)], COMMIT [commit(7)], RELEASE SAVEPOINT [release_savepoint(7)], ROLLBACK [rollback(7)], SAVEPOINT [savepoint(7)] SQL - Language Statements 2010-05-14 ROLLBACK TO SAVEPOINT(7)
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