Postgresql 如何引用外键表两次？

我得到以下错误：

u'detail'：u“一个或多个映射程序未能初始化-无法继续 初始化其他映射程序。原始异常为：无法 不确定上的父/子表之间的联接条件 relationship Vote.user-存在多个外键路径链接 表。指定'foreign_keys'参数，提供 应计为包含外键的列 对父表的引用。“

表

A

被定义为：

class User(postgres.Model):

    def __init__(self,
        name
    ):
        self.name = name

    id = postgres.Column(postgres.Integer , primary_key=True , autoincrement=True)
    name = postgres.Column(postgres.String(32) , nullable=False , unique=True)

class Vote(postgres.Model):

    def __init__(self,
        user_id,
        responder_id,
        #timestamp_request,
        #timestamp_respond,
        value 
    ):
        self.user_id = user_id
        self.responder_id = responder_id
        #self.timestamp_request = timestamp_request
        #self.timestamp_respond = timestamp_respond
        self.value = value

    id = postgres.Column(postgres.Integer , primary_key=True , autoincrement=True)
    user_id = postgres.Column(postgres.Integer , postgres.ForeignKey('user.id'))
    user = postgres.relationship(User , backref=postgres.backref('votes_user'))
    responder_id = postgres.Column(postgres.Integer , postgres.ForeignKey('user.id'))
    responder = postgres.relationship(User , backref=postgres.backref('votes_responder'))
    timestamp_request = postgres.Column(postgres.DateTime , default=datetime.datetime.utcnow , nullable=False , unique=False)
    timestamp_respond = postgres.Column(postgres.DateTime , default=datetime.datetime.utcnow , onupdate=datetime.datetime.utcnow , nullable=False , unique=False)
    value = postgres.Column(postgres.Enum('up' , 'down' , name='vote_value_enum') , nullable=True)

表

B

的定义如下：

class User(postgres.Model):

    def __init__(self,
        name
    ):
        self.name = name

    id = postgres.Column(postgres.Integer , primary_key=True , autoincrement=True)
    name = postgres.Column(postgres.String(32) , nullable=False , unique=True)

class Vote(postgres.Model):

    def __init__(self,
        user_id,
        responder_id,
        #timestamp_request,
        #timestamp_respond,
        value 
    ):
        self.user_id = user_id
        self.responder_id = responder_id
        #self.timestamp_request = timestamp_request
        #self.timestamp_respond = timestamp_respond
        self.value = value

    id = postgres.Column(postgres.Integer , primary_key=True , autoincrement=True)
    user_id = postgres.Column(postgres.Integer , postgres.ForeignKey('user.id'))
    user = postgres.relationship(User , backref=postgres.backref('votes_user'))
    responder_id = postgres.Column(postgres.Integer , postgres.ForeignKey('user.id'))
    responder = postgres.relationship(User , backref=postgres.backref('votes_responder'))
    timestamp_request = postgres.Column(postgres.DateTime , default=datetime.datetime.utcnow , nullable=False , unique=False)
    timestamp_respond = postgres.Column(postgres.DateTime , default=datetime.datetime.utcnow , onupdate=datetime.datetime.utcnow , nullable=False , unique=False)
    value = postgres.Column(postgres.Enum('up' , 'down' , name='vote_value_enum') , nullable=True)

---

SQLAlchemy无法发现关系路径

user_id = Column(ForeignKey('user.id'))
user = relationship(User, backref=backref('votes_user'))
responder_id = Column(ForeignKey('user.id'))
responder = relationship(User, backref=backref('votes_responder'))

responder

关系是否必须使用

responder\u id

或

user\u id

加入？我知道这对我们来说是显而易见的，但是SQLAlchemy在这里不考虑列名。您可以将

responder\u id

重命名为

foobar

，这没有什么区别

定义要用于每个关系的外键

user = relationship(User, foreign_keys=[user_id], backref=backref('votes_user'))
responder = relationship(User, foreign_keys=[responder_id], backref=backref('votes_responder'))