class Transaction in Drupal 9

A wrapper class for creating and managing database transactions.

Not all databases or database configurations support transactions. For example, MySQL MyISAM tables do not. It is also easy to begin a transaction and then forget to commit it, which can lead to connection errors when another transaction is started.

This class acts as a wrapper for transactions. To begin a transaction, simply instantiate it. When the object goes out of scope and is destroyed it will automatically commit. It also will check to see if the specified connection supports transactions. If not, it will simply skip any transaction commands, allowing user-space code to proceed normally. The only difference is that rollbacks won't actually do anything.

In the vast majority of cases, you should not instantiate this class directly. Instead, call ->startTransaction(), from the appropriate connection object.

Hierarchy

• class \Drupal\Core\Database\Transaction

1 file declares its use of Transaction

Transaction.php in core/tests/fixtures/database_drivers/module/corefake/src/Driver/Database/corefakeWithAllCustomClasses/Transaction.php

3 string references to 'Transaction'

Connection::getDriverClass in core/lib/Drupal/Core/Database/Connection.php

Gets the driver-specific override class if any for the specified class.

Connection::startTransaction in core/lib/Drupal/Core/Database/Connection.php

Returns a new DatabaseTransaction object on this connection.

ConnectionTest::providerGetDriverClass in core/tests/Drupal/Tests/Core/Database/ConnectionTest.php

Data provider for testGetDriverClass().

File

core/lib/Drupal/Core/Database/Transaction.php, line 24

Namespace

Drupal\Core\Database

class Transaction {

  /**
   * The connection object for this transaction.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $connection;

  /**
   * A boolean value to indicate whether this transaction has been rolled back.
   *
   * @var bool
   */
  protected $rolledBack = FALSE;

  /**
   * The name of the transaction.
   *
   * This is used to label the transaction savepoint. It will be overridden to
   * 'drupal_transaction' if there is no transaction depth.
   *
   * @var string
   */
  protected $name;
  public function __construct(Connection $connection, $name = NULL) {
    $this->connection = $connection;

    // If there is no transaction depth, then no transaction has started. Name
    // the transaction 'drupal_transaction'.
    if (!($depth = $connection
      ->transactionDepth())) {
      $this->name = 'drupal_transaction';
    }
    elseif (!$name) {
      $this->name = 'savepoint_' . $depth;
    }
    else {
      $this->name = $name;
    }
    $this->connection
      ->pushTransaction($this->name);
  }
  public function __destruct() {

    // If we rolled back then the transaction would have already been popped.
    if (!$this->rolledBack) {
      $this->connection
        ->popTransaction($this->name);
    }
  }

  /**
   * Retrieves the name of the transaction or savepoint.
   */
  public function name() {
    return $this->name;
  }

  /**
   * Rolls back the current transaction.
   *
   * This is just a wrapper method to rollback whatever transaction stack we are
   * currently in, which is managed by the connection object itself. Note that
   * logging (preferable with watchdog_exception()) needs to happen after a
   * transaction has been rolled back or the log messages will be rolled back
   * too.
   *
   * @see \Drupal\Core\Database\Connection::rollBack()
   * @see watchdog_exception()
   */
  public function rollBack() {
    $this->rolledBack = TRUE;
    $this->connection
      ->rollBack($this->name);
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Transaction::$connection	protected	property	The connection object for this transaction.
Transaction::$name	protected	property	The name of the transaction.
Transaction::$rolledBack	protected	property	A boolean value to indicate whether this transaction has been rolled back.
Transaction::name	public	function	Retrieves the name of the transaction or savepoint.
Transaction::rollBack	public	function	Rolls back the current transaction.
Transaction::__construct	public	function
Transaction::__destruct	public	function