public function isDownload()
    {
        $db = \ChameleonSystem\CoreBundle\ServiceLocator::get('database_connection');
        $query = 'select COUNT(*) AS matches FROM `shop_order_item_download_cms_document_mlt`
                   WHERE `source_id` = :shopOrderItemId';
        $result = $db->fetchAssoc($query, array('shopOrderItemId' => $this->id));

        return intval($result['matches']) > 0;
    }