protected function deleteLinkedFieldValues($field_id)
    {
        $sql = 'DELETE fvt
                FROM field_value_translation AS fvt
                WHERE fvt.field_value_id IN (SELECT DISTINCT(fv.field_value_id)
                FROM field_value AS fv
                INNER JOIN field_value AS fv2
                ON (fv.field_value_id = fv2.field_value_id)
                WHERE fv.field_id = ?)';

        return (bool) $this->db->run($sql, array($field_id))->rowCount();
    }