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IBM DB2 Funções
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# db2_rollback

(PECL ibm_db2 >= 1.0.0)

db2_rollback — Rolls back a transaction

### Descrição

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.

### Parâmetros

`connection`

  A valid database connection resource variable as returned from db2_connect() or db2_pconnect().

### Valor Retornado

Retorna `TRUE` em caso de sucesso ou `FALSE` em falhas.

### Exemplos

Exemplo #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);
}
?>`

O exemplo acima irá imprimir:

    7
    0
    7

### Veja Também

- db2_autocommit() - Returns or sets the AUTOCOMMIT state for a database connection
- db2_commit() - Commits a transaction

db2_result
db2_server_info
IBM DB2 Funções
PHP Manual