mysqli::rollback

mysqli_rollback

(PHP 5)

mysqli::rollback -- mysqli_rollback — Rolls back current transaction

Descrição

Object oriented style (method):

bool mysqli::rollback ( void )

Procedural style:

bool mysqli_rollback ( mysqli $link )

Rollbacks the current transaction for the database.

Parâmetros

link: Apenas para estilo de procedimento: Um identificador de conexão retornado por mysqli_connect() or mysqli_init()

Valor Retornado

Retorna TRUE em caso de sucesso ou FALSE em falhas.

Exemplos

Exemplo #1 Object oriented style


<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* disable autocommit */
$mysqli->autocommit(FALSE);

$mysqli->query("CREATE TABLE myCity LIKE City");
$mysqli->query("ALTER TABLE myCity Type=InnoDB");
$mysqli->query("INSERT INTO myCity SELECT * FROM City LIMIT 50");

/* commit insert */
$mysqli->commit();

/* delete all rows */
$mysqli->query("DELETE FROM myCity");

if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
    $row = $result->fetch_row();
    printf("%d rows in table myCity.\n", $row[0]);
    /* Free result */
    $result->close();
}

/* Rollback */
$mysqli->rollback();

if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
    $row = $result->fetch_row();
    printf("%d rows in table myCity (after rollback).\n", $row[0]);
    /* Free result */
    $result->close();
}

/* Drop table myCity */
$mysqli->query("DROP TABLE myCity");

$mysqli->close();
?>

Exemplo #2 Procedural style


<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* disable autocommit */
mysqli_autocommit($link, FALSE);

mysqli_query($link, "CREATE TABLE myCity LIKE City");
mysqli_query($link, "ALTER TABLE myCity Type=InnoDB");
mysqli_query($link, "INSERT INTO myCity SELECT * FROM City LIMIT 50");

/* commit insert */
mysqli_commit($link);

/* delete all rows */
mysqli_query($link, "DELETE FROM myCity");

if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
    $row = mysqli_fetch_row($result);
    printf("%d rows in table myCity.\n", $row[0]);
    /* Free result */
    mysqli_free_result($result);
}

/* Rollback */
mysqli_rollback($link);

if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
    $row = mysqli_fetch_row($result);
    printf("%d rows in table myCity (after rollback).\n", $row[0]);
    /* Free result */
    mysqli_free_result($result);
}

/* Drop table myCity */
mysqli_query($link, "DROP TABLE myCity");

mysqli_close($link);
?>

O exemplo acima irá imprimir:

0 rows in table myCity.
50 rows in table myCity (after rollback).

Veja Também

mysqli_commit() - Salva a transação atual
mysqli_autocommit() - Ativa ou desativa o salvar automaticamente as modificações no banco de dados

add a note User Contributed Notes
mysqli::rollback

jd at dilltree dot com
22-Jul-2009 09:08


Something to consider when using transact is that you should not perform a normal query on the same table (such as a DELETE) immediately after a transaction.  If the transaction rolls-back, the DELETE will execute and even show affected rows, but the row can be magically re-inserted even if the rollback() command comes before the DELETE query.

Lorenzo - webmaster AT 4tour DOT it
10-Feb-2009 12:31


This is an example to explain the powerful of the rollback and commit functions.


Let's suppose you want to be sure that all queries have to be executed without errors before writing data on the database.


Here's the code:





<?php


$all_query_ok=true; // our control variable





//we make 4 inserts, the last one generates an error


//if at least one query returns an error we change our control variable


$mysqli->query("INSERT INTO myCity (id) VALUES (100)") ? null : $all_query_ok=false;


$mysqli->query("INSERT INTO myCity (id) VALUES (200)") ? null : $all_query_ok=false;


$mysqli->query("INSERT INTO myCity (id) VALUES (300)") ? null : $all_query_ok=false;


$mysqli->query("INSERT INTO myCity (id) VALUES (100)") ? null : $all_query_ok=false; //duplicated PRIMARY KEY VALUE





//now let's test our control variable


$all_query_ok ? $mysqli->commit() : $mysqli->rollback();





$mysqli->close();


?>





hope to be helpful!

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Last updated: Fri, 13 Nov 2009