(PHP 5, PHP 7, PHP 8)
mysqli::autocommit -- mysqli_autocommit — Aktiviert oder deaktiviert das automatische Bestätigen von Datenbankänderungen
Objektorientierter Stil
Prozeduraler Stil
Aktiviert oder deaktiviert den Autocommit-Modus für Abfragen an die Datenbankverbindung.
Um den aktuellen Status von Autocommit festzustellen, ist die SQL-Anweisung
SELECT @@autocommit zu verwenden.
mysqlNur bei prozeduralem Aufruf: ein von mysqli_connect() oder mysqli_init() zurückgegebenes mysqli-Objekt.
enableLegt fest, ob Autocommit aktiviert werden soll oder nicht.
If mysqli error reporting is enabled (MYSQLI_REPORT_ERROR) and the requested operation fails,
a warning is generated. If, in addition, the mode is set to MYSQLI_REPORT_STRICT,
a mysqli_sql_exception is thrown instead.
Beispiel #1 mysqli::autocommit()-Beispiel
Objektorientierter Stil
<?php
/* mysqli anweisen, eine Ausnahme auszulösen, wenn ein Fehler auftritt */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* Die Tabellen-Engine muss Transaktionen unterstützen */
$mysqli->query("CREATE TABLE IF NOT EXISTS language (
Code text NOT NULL,
Speakers int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");
/* autocommit ausschalten */
$mysqli->autocommit(false);
$result = $mysqli->query("SELECT @@autocommit");
$row = $result->fetch_row();
printf("Autocommit ist %s\n", $row[0]);
try {
/* Insert-Anweisung vorbereiten */
$stmt = $mysqli->prepare('INSERT INTO language(Code, Speakers) VALUES (?,?)');
$stmt->bind_param('ss', $language_code, $native_speakers);
/* Ein paar Werte einfügen */
$language_code = 'DE';
$native_speakers = 50_123_456;
$stmt->execute();
$language_code = 'FR';
$native_speakers = 40_546_321;
$stmt->execute();
/* Bestätigen der Daten in der Datenbank. Dies setzt nicht autocommit=true */
$mysqli->commit();
print "2 Datensätze in der Datenbank bestätigt\n";
$result = $mysqli->query("SELECT @@autocommit");
$row = $result->fetch_row();
printf("Autocommit ist %s\n", $row[0]);
/* Versuchen, weitere Werte einzufügen */
$language_code = 'PL';
$native_speakers = 30_555_444;
$stmt->execute();
$language_code = 'DK';
$native_speakers = 5_222_444;
$stmt->execute();
/* Das Setzen von autocommit=true löst eine Bestätigung aus */
$mysqli->autocommit(true);
print "2 weitere Datensätze in der Datenbank bestätigt\n";
} catch (mysqli_sql_exception $exception) {
$mysqli->rollback();
throw $exception;
}Prozeduraler Stil
<?php
/* mysqli anweisen, eine Ausnahme auszulösen, wenn ein Fehler auftritt */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");
/* Die Tabellen-Engine muss Transaktionen unterstützen */
mysqli_query($mysqli, "CREATE TABLE IF NOT EXISTS language (
Code text NOT NULL,
Speakers int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");
/* autocommit ausschalten */
mysqli_autocommit($mysqli, false);
$result = mysqli_query($mysqli, "SELECT @@autocommit");
$row = mysqli_fetch_row($result);
printf("Autocommit ist %s\n", $row[0]);
try {
/* Insert-Anweisung vorbereiten */
$stmt = mysqli_prepare($mysqli, 'INSERT INTO language(Code, Speakers) VALUES (?,?)');
mysqli_stmt_bind_param($stmt, 'ss', $language_code, $native_speakers);
/* Ein paar Werte einfügen */
$language_code = 'DE';
$native_speakers = 50_123_456;
mysqli_stmt_execute($stmt);
$language_code = 'FR';
$native_speakers = 40_546_321;
mysqli_stmt_execute($stmt);
/* Bestätigen der Daten in der Datenbank. Dies setzt nicht autocommit=true */
mysqli_commit($mysqli);
print "2 Datensätze in der Datenbank bestätigt\n";
$result = mysqli_query($mysqli, "SELECT @@autocommit");
$row = mysqli_fetch_row($result);
printf("Autocommit ist %s\n", $row[0]);
/* Versuchen, weitere Werte einzufügen */
$language_code = 'PL';
$native_speakers = 30_555_444;
mysqli_stmt_execute($stmt);
$language_code = 'DK';
$native_speakers = 5_222_444;
mysqli_stmt_execute($stmt);
/* Das Setzen von autocommit=true löst eine Bestätigung aus */
mysqli_autocommit($mysqli, true);
print "2 weitere Datensätze in der Datenbank bestätigt\n";
} catch (mysqli_sql_exception $exception) {
mysqli_rollback($mysqli);
throw $exception;
}Die obigen Bespiele erzeugen folgende Ausgabe:
Autocommit ist 0 2 Datensätze in der Datenbank bestätigt Autocommit ist 0 2 weitere Datensätze in der Datenbank bestätigt Autocommit ist 0 2 Datensätze in der Datenbank bestätigt Autocommit ist 0 2 weitere Datensätze in der Datenbank bestätigt
Hinweis:
Die Funktion kann nicht mit Tabellentypen verwendet werden, die keine Transaktionen unterstützen (wie MyISAM oder ISAM).
Just to be clear, autocommit not only turns on/off transactions, but will also 'commit' any waiting queries.<?phpmysqli_autocommit($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.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.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.