def get_slice_db(self, fid):
sql = '<STR_LIT>'<EOL>req = self.cursor.execute(sql, [fid, ])<EOL>if req:<EOL><INDENT>return [r[<NUM_LIT:0>] for r in req]<EOL><DEDENT>else:<EOL><INDENT>return None<EOL><DEDENT>
从数据库中取得fid的所有分片.

        返回的是一个list, 里面是按顺序排好的md5的值