protected function _goDown(AbstractQuery $oQuery, OutputInterface $oOutput = null)
    {
        if (!$this->isExecuted($oQuery)) {
            return false;
        }

        if ($oOutput) {
            $oOutput->writeLn(
                sprintf(
                    '[DEBUG] Migrating down %s %s',
                    $oQuery->getTimestamp(),
                    $oQuery->getClassName()
                )
            );
        }

        $oQuery->down();
        $this->setUnexecuted($oQuery);

        return true;
    }