public function getDescription()
    {
        $changes = array();
        if ($count = $this->countAddedTables()) {
            $changes[] = sprintf('%d added tables', $count);
        }
        if ($count = $this->countRemovedTables()) {
            $changes[] = sprintf('%d removed tables', $count);
        }
        if ($count = $this->countModifiedTables()) {
            $changes[] = sprintf('%d modified tables', $count);
        }
        if ($count = $this->countRenamedTables()) {
            $changes[] = sprintf('%d renamed tables', $count);
        }

        return implode(', ', $changes);
    }