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mysqli::autocommit

mysqli_autocommit

(PHP 5, PHP 7)

mysqli::autocommit -- mysqli_autocommitActive ou désactive le mode auto-commit

Description

Style orienté objet

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

Style procédural

mysqli_autocommit ( mysqli $link , bool $mode ) : 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

link

Seulement en style procédural : Un identifiant de lien retourné par la fonction mysqli_connect() ou par la fonction mysqli_init()

mode

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.

Notes

Note:

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

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($mysqlifalse);

$result mysqli_query($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($mysqlitrue);

    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

Voir aussi

add a note add a note

User Contributed Notes 4 notes

up
14
Geoffrey Thubron
13 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.
up
18
jcwebb at dicoe dot com
13 years ago
Just to be clear, autocommit not only turns on/off transactions, but will also 'commit' any waiting queries.
<?php
mysqli_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.
up
2
Glen
13 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.
up
-8
will at phpfever dot com
14 years ago
If you are using the mysql command line tool, here are some helpful hints for the autocommit feature:

1.  To view the current autocommit setting, you can use this query: select @@autocommit;  It will return the current setting as 1 or 0 (on or off)

2. You can manage the default autocommit feature in you my.cnf or my.ini by adding the following line: init_connect='set autocommit=0'.  I'm pretty sure this isn't in the documentation, but it does work.

Here are the current engines, as of MySQL 5.1dev that support transactions:

InnoDB
BerkeleyDB
Falcon

Falcon is very new, so beware using it on production systems.
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