Sqlalchemy 在多个外键上组合唯一键

鉴于这些SQLAlchemy模型：

class Key():
    key_id = Column('id', Integer, primary_key=True, autoincrement=True)
    name = Column(String(255))

class House():
    house_id = Column('id', Integer, primary_key=True, autoincrement=True)
    name = Column(String(255))

class HouseKey():
    house_key_id = Column('id', Integer, primary_key=True, autoincrement=True)
    house_id = Column(Integer, ForeignKey('house.id'))
    key_id = Column(Integer, ForeignKey('key.id'))

    UniqueConstraint('house_id', 'key_id')

    house = relationship('House', foreign_keys=[house_id])
    key = relationship('Key', foreign_keys=[key_id])

未创建

house\u id，key\u id

唯一密钥。我相信这就是原因（如果我错了，请纠正我）

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如何在同时也是外键的列上创建复合唯一键？

表级

唯一约束：

class HouseKey(Base):
    ...
    __table_args__ = (UniqueConstraint("house_id", "key_id"),)