[英]Ambiguous foreign key in self-referencing table [SQLAlchemy/Alembic]
[英]SQLAlchemy Ambiguous Foreign Key
我有两个类, User
和Address
。 一个用户可以有多个地址和一个默认地址。 我试过这个 SQLAlchemy 代码。
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)
它导致错误
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.
我尝试将foreign_keys
添加到关系中,但我做对了。
这不是正确的方法,您应该从用户表的 default_adderess_id 中删除外键。 如果您想区分默认地址和其他地址,您可以在地址表中再增加一个字段作为类型
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