236 lines
9.2 KiB
PHP
236 lines
9.2 KiB
PHP
<?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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use yii\base\NotSupportedException;
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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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* } catch (\Throwable $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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* > Note: in the above code we have two catch-blocks for compatibility
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* > with PHP 5.x and PHP 7.x. `\Exception` implements the [`\Throwable` interface](https://secure.php.net/manual/en/class.throwable.php)
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* > since PHP 7.0, so you can skip the part with `\Exception` if your app uses only PHP 7.0 and higher.
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*
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* @property bool $isActive Whether this transaction is active. Only an active transaction can [[commit()]] or
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* [[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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* @property int $level The current nesting level of the transaction. This property is read-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\BaseObject
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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 int 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 bool 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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*
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* Starting from version 2.0.16, this method throws exception when beginning nested transaction and underlying DBMS
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* does not support savepoints.
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* @throws InvalidConfigException if [[db]] is `null`
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* @throws NotSupportedException if the DBMS does not support nested transactions
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* @throws Exception if DB connection fails
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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::debug('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::debug('Set savepoint ' . $this->_level, __METHOD__);
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$schema->createSavepoint('LEVEL' . $this->_level);
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} else {
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Yii::info('Transaction not started: nested transaction not supported', __METHOD__);
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throw new NotSupportedException('Transaction not started: nested transaction not supported.');
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}
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$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 ($this->_level === 0) {
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Yii::debug('Commit transaction', __METHOD__);
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$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::debug('Release savepoint ' . $this->_level, __METHOD__);
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$schema->releaseSavepoint('LEVEL' . $this->_level);
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} else {
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Yii::info('Transaction not committed: nested transaction not supported', __METHOD__);
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}
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}
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/**
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* Rolls back a transaction.
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*/
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public function rollBack()
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{
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if (!$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::debug('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::debug('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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}
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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::debug('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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* @return int The current nesting level of the transaction.
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* @since 2.0.8
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*/
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public function getLevel()
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{
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return $this->_level;
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}
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}
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