(PHP 5, PHP 7, PHP 8)
mysqli::autocommit -- mysqli_autocommit — Activa o desactiva el modo auto-commit
Estilo orientado a objetos
Estilo procedimental
Activa o desactiva el modo auto-commit para las consultas en la conexión.
Para verificar el estado del auto-commit, se puede utilizar el comando SQL
SELECT @@autocommit.
mysqlSolo estilo procedimental: Un objeto mysqli devuelto por mysqli_connect() o mysqli_init()
enableSi se debe activar o no el auto-commit.
Si el informe de errores de mysqli está habilitado (MYSQLI_REPORT_ERROR) y la operación solicitada falla,
se genera una advertencia. Si, además, el modo está configurado como MYSQLI_REPORT_STRICT,
se lanza una mysqli_sql_exception en su lugar.
Ejemplo #1 Ejemplo con mysqli::autocommit()
Estilo orientado a objetos
<?php
/* Solicita a mysqli que lance una excepción si ocurre un error */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* El motor de tabla soporta transacciones */
$mysqli->query("CREATE TABLE IF NOT EXISTS language (
Code text NOT NULL,
Speakers int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");
/* Desactiva el autocommit */
$mysqli->autocommit(false);
$result = $mysqli->query("SELECT @@autocommit");
$row = $result->fetch_row();
printf("El Autocommit vale %s\n", $row[0]);
try {
/* Prepara una consulta de inserción */
$stmt = $mysqli->prepare('INSERT INTO language(Code, Speakers) VALUES (?,?)');
$stmt->bind_param('ss', $language_code, $native_speakers);
/* Inserta varios valores */
$language_code = 'DE';
$native_speakers = 50_123_456;
$stmt->execute();
$language_code = 'FR';
$native_speakers = 40_546_321;
$stmt->execute();
/* Confirma los datos en la base de datos. Esto no activa el autocommit */
$mysqli->commit();
print "Confirmación de 2 líneas en la base de datos\n";
$result = $mysqli->query("SELECT @@autocommit");
$row = $result->fetch_row();
printf("El autocommit vale %s\n", $row[0]);
/* Intenta insertar varios valores */
$language_code = 'PL';
$native_speakers = 30_555_444;
$stmt->execute();
$language_code = 'DK';
$native_speakers = 5_222_444;
$stmt->execute();
/* Establecer autocommit=true provocará el commit */
$mysqli->autocommit(true);
print "Confirmación de 2 líneas en la base de datos\n";
} catch (mysqli_sql_exception $exception) {
$mysqli->rollback();
throw $exception;
}Estilo procedimental
<?php
/* Solicita a mysqli que lance una excepción si ocurre un error */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");
/* El motor de tabla soporta transacciones */
mysqli_query($mysqli, "CREATE TABLE IF NOT EXISTS language (
Code text NOT NULL,
Speakers int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");
/* Desactiva el autocommit */
mysqli_autocommit($mysqli, false);
$result = mysqli_query($mysqli, "SELECT @@autocommit");
$row = mysqli_fetch_row($result);
printf("El Autocommit vale %s\n", $row[0]);
try {
/* Prepara una consulta de inserción */
$stmt = mysqli_prepare($mysqli, 'INSERT INTO language(Code, Speakers) VALUES (?,?)');
mysqli_stmt_bind_param($stmt, 'ss', $language_code, $native_speakers);
/* Inserta varios valores */
$language_code = 'DE';
$native_speakers = 50_123_456;
mysqli_stmt_execute($stmt);
$language_code = 'FR';
$native_speakers = 40_546_321;
mysqli_stmt_execute($stmt);
/* Confirma los datos en la base de datos. Esto no activa el autocommit */
mysqli_commit($mysqli);
print "Confirmación de 2 líneas en la base de datos\n";
$result = mysqli_query($mysqli, "SELECT @@autocommit");
$row = mysqli_fetch_row($result);
printf("El autocommit vale %s\n", $row[0]);
/* Intenta insertar varios valores */
$language_code = 'PL';
$native_speakers = 30_555_444;
mysqli_stmt_execute($stmt);
$language_code = 'DK';
$native_speakers = 5_222_444;
mysqli_stmt_execute($stmt);
/* Establecer autocommit=true provocará el commit */
mysqli_autocommit($mysqli, true);
print "Confirmación de 2 líneas en la base de datos\n";
} catch (mysqli_sql_exception $exception) {
mysqli_rollback($mysqli);
throw $exception;
}Los ejemplos anteriores mostrarán:
El autocommit vale 0 Confirmación de 2 líneas en la base de datos El autocommit vale 0 Confirmación de 2 líneas en la base de datos El autocommit vale 0 Confirmación de 2 líneas en la base de datos El autocommit vale 0 Confirmación de 2 líneas en la base de datos
Nota:
Esta función no funciona con los tipos de tablas no transaccionales, como MyISAM o ISAM.
Just to be clear, autocommit not only turns on/off transactions, but will also 'commit' any waiting queries.
<?php
mysqli_autocommit($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.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.