如何在Joomla 1.5中创建SQL事务？

Question

I've successfully created a component in Joomla where a user can update database content. The problem is I have two queries to execute, if the second query fails, the changes done by first query should be discarded. I have tried these codes and it's not giving me rollback:

    $db = JFactory::getDBO();

    $db->setQuery("BEGIN");
    $db->query();
    $db->setQuery($delete_script);
    $db->query();
    $db->setQuery($update_script);
    $db->query();

    if($db->getErrorMsg())
    {
        $db->setQuery("ROLLBACK");
        $db->query();
        JFactory::getApplication()->enqueueMessage(JText::_($sql_script . 'An error occurred while saving loan types. Please check formatting and try again.'), 'error');
    }
    else
    {
        $db->setQuery("COMMIT");
        $db->query();
        JFactory::getApplication()->enqueueMessage(JText::_('Loan types have been saved successfully!'), 'message');

    }

    JRequest::setVar( 'view', 'loantypes' );
    parent::display();

So how do you create a transaction in Joomla 1.5?

Answer 1

You should perform like this:

$db = JFactory::getDBO();

$db->setQuery("BEGIN");
$db->query();

$db->setQuery($delete_script);
$db->query();
if($db->getErrorMsg()) {
    $db->setQuery("ROLLBACK");
    $db->query();
    JFactory::getApplication()->enqueueMessage(JText::_($sql_script . 'An error occurred while saving loan types. Please check formatting and try again.'), 'error');
}
$db->setQuery($update_script);
$db->query();

if(!$db->getErrorMsg()) {
    $db->setQuery("COMMIT");
    $db->query();
    JFactory::getApplication()->enqueueMessage(JText::_('Loan types have been saved successfully!'), 'message');

}

JRequest::setVar( 'view', 'loantypes' );
parent::display();

Rollback must be performed on recent executed query.