db2_rollback
(no version information, might be only in CVS)
db2_rollback --
Rolls back a transaction
Descripción
bool
db2_rollback ( resource connection )
Rolls back an in-progress transaction on the specified connection resource and
begins a new transaction. PHP applications normally default to AUTOCOMMIT
mode, so db2_rollback() normally has no effect unless
AUTOCOMMIT has been turned off for the connection resource.
Nota:
If the specified connection resource is a persistent connection, all
transactions in progress for all applications using that persistent
connection will be rolled back. For this reason, persistent connections
are not recommended for use in applications that require transactions.
Valores retornados
Devuelve TRUE si todo se
llevó a cabo correctamente, FALSE en caso
de fallo.
Ejemplos
Ejemplo 1. Rolling back a DELETE statement
In the following example, we count the number of rows in a table, turn
off AUTOCOMMIT mode on a database connection, delete all of the rows in
the table and return the count of 0 to prove that the
rows have been removed. We then issue db2_rollback()
and return the updated count of rows in the table to show that the number
is the same as before we issued the DELETE statement. The return to the
original state of the table demonstrates that the roll back of the
transaction succeeded.
<?php $conn = db2_connect($database, $user, $password);
if ($conn) { $stmt = db2_exec($conn, "SELECT count(*) FROM animals"); $res = db2_fetch_array( $stmt ); echo $res[0] . "\n"; // Turn AUTOCOMMIT off db2_autocommit($conn, DB2_AUTOCOMMIT_OFF); // Delete all rows from ANIMALS db2_exec($conn, "DELETE FROM animals"); $stmt = db2_exec($conn, "SELECT count(*) FROM animals"); $res = db2_fetch_array( $stmt ); echo $res[0] . "\n"; // Roll back the DELETE statement db2_rollback( $conn ); $stmt = db2_exec( $conn, "SELECT count(*) FROM animals" ); $res = db2_fetch_array( $stmt ); echo $res[0] . "\n"; db2_close($conn); } ?>
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El resultado del ejemplo seria: |