SQLAlchemy 歧義外鍵

Question

我有兩個類， User和Address 。 一個用戶可以有多個地址和一個默認地址。 我試過這個 SQLAlchemy 代碼。

from sqlalchemy import create_engine
from sqlalchemy import Column, Integer, String
from sqlalchemy import ForeignKey

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.orm import sessionmaker, relationship


engine = create_engine('sqlite:///:memory:', echo=True)

Base = declarative_base()


class User(Base):
    __tablename__ = 'users'

    id = Column(Integer, primary_key=True)
    default_address_id = Column(Integer, ForeignKey('addresses.id'))
    name = Column(String)
    fullname = Column(String)
    nickname = Column(String)

    addresses = relationship("Address", order_by="Address.id", back_populates="user")


class Address(Base):
    __tablename__ = 'addresses'
    id = Column(Integer, primary_key=True)
    email_address = Column(String, nullable=False)
    user_id = Column(Integer, ForeignKey('users.id'))

    user = relationship("User", back_populates="addresses")


Base.metadata.create_all(engine)

它導致錯誤

sqlalchemy.exc.AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship User.addresses - there are multiple foreign key paths linking the tables.  Specify the 'foreign_keys' argument, providing a list of those columns which should be counted as containing a foreign key reference to the parent table.

我嘗試將foreign_keys添加到關系中，但我做對了。

Answer 1

這不是正確的方法，您應該從用戶表的 default_adderess_id 中刪除外鍵。 如果您想區分默認地址和其他地址，您可以在地址表中再增加一個字段作為類型