mysqli::autocommit

mysqli_autocommit

(PHP 5, PHP 7, PHP 8)

mysqli::autocommit -- mysqli_autocommit — Active ou désactive le mode auto-commit

Description

Style orienté objet

public mysqli::autocommit(bool $enable): bool

Style procédural

mysqli_autocommit(mysqli $mysql, bool $enable): bool

Active ou désactive le mode auto-commit pour les requêtes sur la connexion.

Pour vérifier l'état de l'auto-commit, utilisez la commande SQL SELECT @@autocommit.

Liste de paramètres

mysql: Seulement en style procédural : Un objet mysqli retourné par la fonction mysqli_connect() ou mysqli_init().
enable: Si l'on doit activer ou non l'auto-commit.

Valeurs de retour

Cette fonction retourne true en cas de succès ou false si une erreur survient.

Erreurs / Exceptions

Si le rapport d'erreurs mysqli est activé (MYSQLI_REPORT_ERROR) et que l'opération demandée échoue, un avertissement est généré. Si, en plus, le mode est défini sur MYSQLI_REPORT_STRICT, une mysqli_sql_exception est lancée à la place.

Exemples

Exemple #1 Exemple avec mysqli::autocommit()

Style orienté objet

<?php

/* Demande à mysqli de lancer une exception si une erreur survient */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

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

/* Le moteur de table supporte les transactions */
$mysqli->query("CREATE TABLE IF NOT EXISTS language (
    Code text NOT NULL,
    Speakers int(11) NOT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");

/* Désactive l'autocommit */
$mysqli->autocommit(false);

$result = $mysqli->query("SELECT @@autocommit");
$row = $result->fetch_row();
printf("L'Autocommit vaut %s\n", $row[0]);

try {
    /* Prépare une requête d'insertion */
    $stmt = $mysqli->prepare('INSERT INTO language(Code, Speakers) VALUES (?,?)');
    $stmt->bind_param('ss', $language_code, $native_speakers);

    /* Insère plusieurs valeurs */
    $language_code = 'DE';
    $native_speakers = 50_123_456;
    $stmt->execute();
    $language_code = 'FR';
    $native_speakers = 40_546_321;
    $stmt->execute();

    /* Commit les données dans la base de données. Ceci n'active pas l'autocommit */
    $mysqli->commit();
    print "Validation de 2 lignes dans la base de données\n";

    $result = $mysqli->query("SELECT @@autocommit");
    $row = $result->fetch_row();
    printf("L'autocommit vaut %s\n", $row[0]);

    /* Tente d'insérer plusieurs valeurs */
    $language_code = 'PL';
    $native_speakers = 30_555_444;
    $stmt->execute();
    $language_code = 'DK';
    $native_speakers = 5_222_444;
    $stmt->execute();

    /* Le fait de définir autocommit=true va déclencher le commit */
    $mysqli->autocommit(true);

    print "Validation de 2 lignes dans la base de données\n";
} catch (mysqli_sql_exception $exception) {
    $mysqli->rollback();

    throw $exception;
}

Style procédural

<?php

/* Demande à mysqli de lancer une exception si une erreur survient */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");

/* Le moteur de table supporte les transactions */
mysqli_query($mysqli, "CREATE TABLE IF NOT EXISTS language (
    Code text NOT NULL,
    Speakers int(11) NOT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");

/* Désactive l'autocommit */
mysqli_autocommit($mysqli, false);

$result = mysqli_query($mysqli, "SELECT @@autocommit");
$row = mysqli_fetch_row($result);
printf("L'Autocommit vaut %s\n", $row[0]);

try {
    /* Prépare une requête d'insertion */
    $stmt = mysqli_prepare($mysqli, 'INSERT INTO language(Code, Speakers) VALUES (?,?)');
    mysqli_stmt_bind_param($stmt, 'ss', $language_code, $native_speakers);

    /* Insère plusieurs valeurs */
    $language_code = 'DE';
    $native_speakers = 50_123_456;
    mysqli_stmt_execute($stmt);
    $language_code = 'FR';
    $native_speakers = 40_546_321;
    mysqli_stmt_execute($stmt);

    /* Commit les données dans la base de données. Ceci n'active pas l'autocommit */
    mysqli_commit($mysqli);
    print "Validation de 2 lignes dans la base de données\n";

    $result = mysqli_query($mysqli, "SELECT @@autocommit");
    $row = mysqli_fetch_row($result);
    printf("L'autocommit vaut %s\n", $row[0]);

    /* Tente d'insérer plusieurs valeurs */
    $language_code = 'PL';
    $native_speakers = 30_555_444;
    mysqli_stmt_execute($stmt);
    $language_code = 'DK';
    $native_speakers = 5_222_444;
    mysqli_stmt_execute($stmt);

    /* Le fait de définir autocommit=true va déclencher le commit */
    mysqli_autocommit($mysqli, true);

    print "Validation de 2 lignes dans la base de données\n";
} catch (mysqli_sql_exception $exception) {
    mysqli_rollback($mysqli);

    throw $exception;
}

Les exemples ci-dessus vont afficher :

L'autocommit vaut 0
Validation de 2 lignes dans la base de données
L'autocommit vaut 0
Validation de 2 lignes dans la base de données
L'autocommit vaut 0
Validation de 2 lignes dans la base de données
L'autocommit vaut 0
Validation de 2 lignes dans la base de données

Notes

Note:
Cette fonction ne fonctionne pas avec les types de tables non transactionnelles, comme MyISAM ou ISAM.

Voir aussi

mysqli_begin_transaction() - Démarre une transaction
mysqli_commit() - Valide la transaction courante
mysqli_rollback() - Annule la transaction courante

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User Contributed Notes 3 notes

down

jcwebb at dicoe dot com ¶

17 years ago

Just to be clear, autocommit not only turns on/off transactions, but will also 'commit' any waiting queries.<?phpmysqli_autocommit($link, FALSE); // turn OFF auto-some query 1;-some query 2;mysqli_commit($link); // process ALL queries so far-some query 3;-some query 4;mysqli_autocommit($link, TRUE); // turn ON auto?>All 4 will be processed.

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Geoffrey Thubron ¶

18 years ago

It's worth noting that you can perform transactions without disabling autocommit just using standard sql. "START TRANSACTION;" will start a transaction. "COMMIT;" will commit the results and "ROLLBACK;" will revert to the pre-transaction state.CREATE TABLE and CREATE DATABASE (and probably others) are always commited immediately and your transaction appears to terminate. Thus any commands before and after will be commited, even if a subsequent rollback is attempted.If you are in the middle of a transaction and you call mysqli_close() it appears that you get the funcitonality of an implicit rollback.I can't reproduce the "code bug causes lock" problem outlined below (I always get a successful rollback and the script will run umtine times successfully). Therefore, I would suggest that the problem is fixed in php-5.2.2.

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Glen ¶

18 years ago

I've found that if PHP exits due to a code bug during a transaction, an InnoDB table can remain locked until Apache is restarted.The simple test is to start a transaction by setting $mysqli_obj->autocommit(false) and executing an insert statement.  Before getting to a $mysqli_obj->commit statement - have a runtime code bug bomb PHP.  You check the database, no insert happened (you assume a rollback occurred) .. and you go fix the bug, and try again... but this time the script takes about 50 seconds to timeout - the insert statement returning with a “1205 - Lock wait timeout exceeded; try restarting transaction”.  No rollback occurred. And this error will not go away until you restart Apache - for whatever reason, the resources are not released until the process is killed.I found that an ‘exit’, instead of a PHP code bug, will not cause a problem. So there is an auto-rollback mechanism in place - it just fails miserably when PHP dies unexpectantly. Having to restarting apache is a pretty drastic measure to overcome a code bug.To avoid this problem, I use “register_shutdown_function()” when I start a transaction, and set a flag to indicate a transaction is in process (because there is no unregister_shutdown_function()). See below. So the __shutdown_check() routine (I beleive it needs to be public) is called when the script bombs - which is able to invoke the rollback().these are just the relevant bits to give u an idea...<?php public function begin_transaction() {  $ret = $this->mysqli_obj->autocommit(false);  $this->transaction_in_progress = true;  register_shutdown_function(array($this, "__shutdown_check"));}public function __shutdown_check() {  if ($this->transaction_in_progress) {    $this->rollback();  }}public function commit() {  $ret = $this->mysqli_obj->commit();  $this->transaction_in_progress = false;}public function rollback() {  $ret = $this->mysqli_obj->rollback();  $this->transaction_in_progress = false;}?>True for PHP 5.1.6 + MySQL 5.0.24a.

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