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214 lines
8.3 KiB
214 lines
8.3 KiB
<?php |
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/** |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright (c) 2008 Yii Software LLC |
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* @license http://www.yiiframework.com/license/ |
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*/ |
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namespace yii\db; |
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use Yii; |
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use yii\base\InvalidConfigException; |
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/** |
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* Transaction represents a DB transaction. |
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* |
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* It is usually created by calling [[Connection::beginTransaction()]]. |
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* |
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* The following code is a typical example of using transactions (note that some |
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* DBMS may not support transactions): |
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* |
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* ```php |
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* $transaction = $connection->beginTransaction(); |
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* try { |
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* $connection->createCommand($sql1)->execute(); |
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* $connection->createCommand($sql2)->execute(); |
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* //.... other SQL executions |
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* $transaction->commit(); |
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* } catch (\Exception $e) { |
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* $transaction->rollBack(); |
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* throw $e; |
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* } |
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* ``` |
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* |
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* @property boolean $isActive Whether this transaction is active. Only an active transaction can [[commit()]] |
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* or [[rollBack()]]. This property is read-only. |
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* @property string $isolationLevel The transaction isolation level to use for this transaction. This can be |
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* one of [[READ_UNCOMMITTED]], [[READ_COMMITTED]], [[REPEATABLE_READ]] and [[SERIALIZABLE]] but also a string |
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* containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. This property is |
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* write-only. |
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* |
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* @author Qiang Xue <qiang.xue@gmail.com> |
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* @since 2.0 |
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*/ |
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class Transaction extends \yii\base\Object |
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{ |
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/** |
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* A constant representing the transaction isolation level `READ UNCOMMITTED`. |
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* @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels |
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*/ |
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const READ_UNCOMMITTED = 'READ UNCOMMITTED'; |
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/** |
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* A constant representing the transaction isolation level `READ COMMITTED`. |
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* @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels |
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*/ |
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const READ_COMMITTED = 'READ COMMITTED'; |
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/** |
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* A constant representing the transaction isolation level `REPEATABLE READ`. |
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* @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels |
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*/ |
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const REPEATABLE_READ = 'REPEATABLE READ'; |
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/** |
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* A constant representing the transaction isolation level `SERIALIZABLE`. |
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* @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels |
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*/ |
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const SERIALIZABLE = 'SERIALIZABLE'; |
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/** |
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* @var Connection the database connection that this transaction is associated with. |
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*/ |
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public $db; |
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/** |
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* @var integer the nesting level of the transaction. 0 means the outermost level. |
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*/ |
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private $_level = 0; |
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/** |
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* Returns a value indicating whether this transaction is active. |
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* @return boolean whether this transaction is active. Only an active transaction |
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* can [[commit()]] or [[rollBack()]]. |
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*/ |
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public function getIsActive() |
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{ |
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return $this->_level > 0 && $this->db && $this->db->isActive; |
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} |
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/** |
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* Begins a transaction. |
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* @param string|null $isolationLevel The [isolation level][] to use for this transaction. |
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* This can be one of [[READ_UNCOMMITTED]], [[READ_COMMITTED]], [[REPEATABLE_READ]] and [[SERIALIZABLE]] but |
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* also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. |
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* If not specified (`null`) the isolation level will not be set explicitly and the DBMS default will be used. |
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* |
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* > Note: This setting does not work for PostgreSQL, where setting the isolation level before the transaction |
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* has no effect. You have to call [[setIsolationLevel()]] in this case after the transaction has started. |
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* |
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* > Note: Some DBMS allow setting of the isolation level only for the whole connection so subsequent transactions |
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* may get the same isolation level even if you did not specify any. When using this feature |
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* you may need to set the isolation level for all transactions explicitly to avoid conflicting settings. |
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* At the time of this writing affected DBMS are MSSQL and SQLite. |
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* |
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* [isolation level]: http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels |
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* @throws InvalidConfigException if [[db]] is `null`. |
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*/ |
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public function begin($isolationLevel = null) |
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{ |
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if ($this->db === null) { |
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throw new InvalidConfigException('Transaction::db must be set.'); |
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} |
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$this->db->open(); |
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if ($this->_level === 0) { |
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if ($isolationLevel !== null) { |
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$this->db->getSchema()->setTransactionIsolationLevel($isolationLevel); |
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} |
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Yii::trace('Begin transaction' . ($isolationLevel ? ' with isolation level ' . $isolationLevel : ''), __METHOD__); |
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$this->db->trigger(Connection::EVENT_BEGIN_TRANSACTION); |
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$this->db->pdo->beginTransaction(); |
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$this->_level = 1; |
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return; |
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} |
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$schema = $this->db->getSchema(); |
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if ($schema->supportsSavepoint()) { |
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Yii::trace('Set savepoint ' . $this->_level, __METHOD__); |
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$schema->createSavepoint('LEVEL' . $this->_level); |
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} else { |
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Yii::info('Transaction not started: nested transaction not supported', __METHOD__); |
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} |
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$this->_level++; |
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} |
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/** |
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* Commits a transaction. |
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* @throws Exception if the transaction is not active |
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*/ |
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public function commit() |
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{ |
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if (!$this->getIsActive()) { |
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throw new Exception('Failed to commit transaction: transaction was inactive.'); |
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} |
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$this->_level--; |
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if ($this->_level === 0) { |
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Yii::trace('Commit transaction', __METHOD__); |
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$this->db->pdo->commit(); |
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$this->db->trigger(Connection::EVENT_COMMIT_TRANSACTION); |
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return; |
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} |
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$schema = $this->db->getSchema(); |
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if ($schema->supportsSavepoint()) { |
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Yii::trace('Release savepoint ' . $this->_level, __METHOD__); |
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$schema->releaseSavepoint('LEVEL' . $this->_level); |
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} else { |
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Yii::info('Transaction not committed: nested transaction not supported', __METHOD__); |
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} |
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} |
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/** |
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* Rolls back a transaction. |
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* @throws Exception if the transaction is not active |
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*/ |
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public function rollBack() |
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{ |
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if (!$this->getIsActive()) { |
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// do nothing if transaction is not active: this could be the transaction is committed |
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// but the event handler to "commitTransaction" throw an exception |
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return; |
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} |
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$this->_level--; |
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if ($this->_level === 0) { |
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Yii::trace('Roll back transaction', __METHOD__); |
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$this->db->pdo->rollBack(); |
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$this->db->trigger(Connection::EVENT_ROLLBACK_TRANSACTION); |
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return; |
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} |
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$schema = $this->db->getSchema(); |
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if ($schema->supportsSavepoint()) { |
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Yii::trace('Roll back to savepoint ' . $this->_level, __METHOD__); |
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$schema->rollBackSavepoint('LEVEL' . $this->_level); |
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} else { |
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Yii::info('Transaction not rolled back: nested transaction not supported', __METHOD__); |
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// throw an exception to fail the outer transaction |
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throw new Exception('Roll back failed: nested transaction not supported.'); |
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} |
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} |
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/** |
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* Sets the transaction isolation level for this transaction. |
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* |
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* This method can be used to set the isolation level while the transaction is already active. |
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* However this is not supported by all DBMS so you might rather specify the isolation level directly |
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* when calling [[begin()]]. |
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* @param string $level The transaction isolation level to use for this transaction. |
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* This can be one of [[READ_UNCOMMITTED]], [[READ_COMMITTED]], [[REPEATABLE_READ]] and [[SERIALIZABLE]] but |
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* also a string containing DBMS specific syntax to be used after `SET TRANSACTION ISOLATION LEVEL`. |
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* @throws Exception if the transaction is not active |
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* @see http://en.wikipedia.org/wiki/Isolation_%28database_systems%29#Isolation_levels |
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*/ |
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public function setIsolationLevel($level) |
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{ |
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if (!$this->getIsActive()) { |
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throw new Exception('Failed to set isolation level: transaction was inactive.'); |
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} |
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Yii::trace('Setting transaction isolation level to ' . $level, __METHOD__); |
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$this->db->getSchema()->setTransactionIsolationLevel($level); |
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} |
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}
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