beginTransaction(); * try { * $connection->createCommand($sql1)->execute(); * $connection->createCommand($sql2)->execute(); * //.... other SQL executions * $transaction->commit(); * } catch (Exception $e) { * $transaction->rollBack(); * } * ~~~ * * @property boolean $isActive Whether this transaction is active. Only an active transaction can [[commit()]] * or [[rollBack()]]. This property is read-only. * @property string $isolationLevel The transaction isolation level to use for this transaction. This can be * one of [[READ_UNCOMMITTED]], [[READ_COMMITTED]], [[REPEATABLE_READ]] and [[SERIALIZABLE]] but also a string * containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. This property is * write-only. * * @author Qiang Xue * @since 2.0 */ class Transaction extends \yii\base\Object { /** * A constant representing the transaction isolation level `READ UNCOMMITTED`. * @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels */ const READ_UNCOMMITTED = 'READ UNCOMMITTED'; /** * A constant representing the transaction isolation level `READ COMMITTED`. * @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels */ const READ_COMMITTED = 'READ COMMITTED'; /** * A constant representing the transaction isolation level `REPEATABLE READ`. * @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels */ const REPEATABLE_READ = 'REPEATABLE READ'; /** * A constant representing the transaction isolation level `SERIALIZABLE`. * @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels */ const SERIALIZABLE = 'SERIALIZABLE'; /** * @var Connection the database connection that this transaction is associated with. */ public $db; /** * @var integer the nesting level of the transaction. 0 means the outermost level. */ private $_level = 0; /** * Returns a value indicating whether this transaction is active. * @return boolean whether this transaction is active. Only an active transaction * can [[commit()]] or [[rollBack()]]. */ public function getIsActive() { return $this->_level > 0 && $this->db && $this->db->isActive; } /** * Begins a transaction. * @param string|null $isolationLevel The [isolation level][] to use for this transaction. * This can be one of [[READ_UNCOMMITTED]], [[READ_COMMITTED]], [[REPEATABLE_READ]] and [[SERIALIZABLE]] but * also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. * If not specified (`null`) the isolation level will not be set explicitly and the DBMS default will be used. * * > Note: This setting does not work for PostgreSQL, where setting the isolation level before the transaction * has no effect. You have to call [[setIsolationLevel()]] in this case after the transaction has started. * * > Note: Some DBMS allow setting of the isolation level only for the whole connection so subsequent transactions * may get the same isolation level even if you did not specify any. When using this feature * you may need to set the isolation level for all transactions explicitly to avoid conflicting settings. * At the time of this writing affected DBMS are MSSQL and SQLite. * * [isolation level]: http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels * @throws InvalidConfigException if [[db]] is `null`. */ public function begin($isolationLevel = null) { if ($this->db === null) { throw new InvalidConfigException('Transaction::db must be set.'); } $this->db->open(); if ($this->_level == 0) { if ($isolationLevel !== null) { $this->db->getSchema()->setTransactionIsolationLevel($isolationLevel); } Yii::trace('Begin transaction' . ($isolationLevel ? ' with isolation level ' . $isolationLevel : ''), __METHOD__); $this->db->trigger(Connection::EVENT_BEGIN_TRANSACTION); $this->db->pdo->beginTransaction(); $this->_level = 1; return; } $schema = $this->db->getSchema(); if ($schema->supportsSavepoint()) { Yii::trace('Set savepoint ' . $this->_level, __METHOD__); $schema->createSavepoint('LEVEL' . $this->_level); } else { Yii::info('Transaction not started: nested transaction not supported', __METHOD__); } $this->_level++; } /** * Commits a transaction. * @throws Exception if the transaction is not active */ public function commit() { if (!$this->getIsActive()) { throw new Exception('Failed to commit transaction: transaction was inactive.'); } $this->_level--; if ($this->_level == 0) { Yii::trace('Commit transaction', __METHOD__); $this->db->pdo->commit(); $this->db->trigger(Connection::EVENT_COMMIT_TRANSACTION); return; } $schema = $this->db->getSchema(); if ($schema->supportsSavepoint()) { Yii::trace('Release savepoint ' . $this->_level, __METHOD__); $schema->releaseSavepoint('LEVEL' . $this->_level); } else { Yii::info('Transaction not committed: nested transaction not supported', __METHOD__); } } /** * Rolls back a transaction. * @throws Exception if the transaction is not active */ public function rollBack() { if (!$this->getIsActive()) { // do nothing if transaction is not active: this could be the transaction is committed // but the event handler to "commitTransaction" throw an exception return; } $this->_level--; if ($this->_level == 0) { Yii::trace('Roll back transaction', __METHOD__); $this->db->pdo->rollBack(); $this->db->trigger(Connection::EVENT_ROLLBACK_TRANSACTION); return; } $schema = $this->db->getSchema(); if ($schema->supportsSavepoint()) { Yii::trace('Roll back to savepoint ' . $this->_level, __METHOD__); $schema->rollBackSavepoint('LEVEL' . $this->_level); } else { Yii::info('Transaction not rolled back: nested transaction not supported', __METHOD__); // throw an exception to fail the outer transaction throw new Exception('Roll back failed: nested transaction not supported.'); } } /** * Sets the transaction isolation level for this transaction. * * This method can be used to set the isolation level while the transaction is already active. * However this is not supported by all DBMS so you might rather specify the isolation level directly * when calling [[begin()]]. * @param string $level The transaction isolation level to use for this transaction. * This can be one of [[READ_UNCOMMITTED]], [[READ_COMMITTED]], [[REPEATABLE_READ]] and [[SERIALIZABLE]] but * also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. * @throws Exception if the transaction is not active * @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels */ public function setIsolationLevel($level) { if (!$this->getIsActive()) { throw new Exception('Failed to set isolation level: transaction was inactive.'); } Yii::trace('Setting transaction isolation level to ' . $level, __METHOD__); $this->db->getSchema()->setTransactionIsolationLevel($level); } }