orm.py 文件源码

def findOne(db, resultantClass, **query):
        ''' (pymongo.database.Database, MongoORM) -> MongoORM
        Creates a MongoORM directly from the Mongo database in db with
        query arguments in the resultantClass.
        '''

        objectData = db[resultantClass.collection].find_one(
            query,

            # in case of tiebreakers, get the newest one
            sort=[('_id', DESCENDING)]
        )
        if objectData:
            return resultantClass(
                db,
                resultantClass.collection,
                **objectData
            )

        # non-existant objectId
        raise KeyError('No such document in %s' % (
            str(db[resultantClass.collection])
        ))