How does \Magento/Framework/DB/Transaction::_startTransaction() work?

dmitrii_fediuk · April 26, 2016, 11:55am

Context: How does a database transaction work?

magento/magento2/blob/720667e/lib/internal/Magento/Framework/DB/Transaction.php#L36-L47


/**
 * Begin transaction for all involved object resources
 *
 * @return $this
 */
protected function _startTransaction()
{
    foreach ($this->_objects as $object) {
        $object->getResource()->beginTransaction();
    }
    return $this;
}

github.com

magento/magento2/blob/720667e/lib/internal/Magento/Framework/Model/ResourceModel/AbstractResource.php#L49-L59


/**
 * Start resource transaction
 *
 * @return $this
 * @api
 */
public function beginTransaction()
{
    $this->getConnection()->beginTransaction();
    return $this;
}

github.com

magento/magento2/blob/720667e/lib/internal/Magento/Framework/Model/ResourceModel/AbstractResource.php#L57-L57


$this->getConnection()->beginTransaction();

github.com

magento/magento2/blob/720667e/lib/internal/Magento/Framework/DB/Adapter/Pdo/Mysql.php#L217-L235


/**
 * Begin new DB transaction for connection
 *
 * @return $this
 * @throws \Exception
 */
public function beginTransaction()
{
    if ($this->_isRolledBack) {
        throw new \Exception(AdapterInterface::ERROR_ROLLBACK_INCOMPLETE_MESSAGE);
    }
    if ($this->_transactionLevel === 0) {
        $this->logger->startTimer();
        parent::beginTransaction();
        $this->logger->logStats(LoggerInterface::TYPE_TRANSACTION, 'BEGIN');
    }
    ++$this->_transactionLevel;
    return $this;
}

github.com

zendframework/zf1/blob/release-1.12.16/library/Zend/Db/Adapter/Abstract.php#L487-L499


/**
 * Leave autocommit mode and begin a transaction.
 *
 * @return Zend_Db_Adapter_Abstract
 */
public function beginTransaction()
{
    $this->_connect();
    $q = $this->_profiler->queryStart('begin', Zend_Db_Profiler::TRANSACTION);
    $this->_beginTransaction();
    $this->_profiler->queryEnd($q);
    return $this;
}

github.com

zendframework/zf1/blob/release-1.12.16/library/Zend/Db/Adapter/Pdo/Abstract.php#L301-L308


/**
 * Begin a transaction.
 */
protected function _beginTransaction()
{
    $this->_connect();
    $this->_connection->beginTransaction();
}

$this->_connection is a PDO instance.
See PDO::beginTransaction().