def delete(self, doc):
        if doc.id is None:
            raise DatabaseException('Document does not have id')
        if doc.sid is None:
            try:
                rs = self.db.docs.remove({'id': doc.id}, safe=True)
                assert rs['n'] == 1
            except Exception as e:
                raise DatabaseException(e)
            return None
        doc.data = None
        return self.update(doc)
def limitStrLessThen128Char(self, strStr=None):
        if len(strStr) > 128:
            logging.info("limit str less then 128 char")
            return strStr[:127] + u"_"
        else:
            return strStr