Question

使用sqlAlchemy，我可以拥有一个包含两个类别Address和Customer的系统，其中我有2个关系1用于计费，1个用于发货。这很简单，文档中有一个简单的例子。如果我决定在类客户中添加所有地址，那么我在类地址中添加一个外键列，我指定地址所属的custumer_id。我无法创建关系，因为它返回以下错误

sqlalchemy.exc.AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship Customer.adresses - 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.

我创建此示例，返回相同的错误

from sqlalchemy import create_engine
from sqlalchemy import Integer, ForeignKey, String, Column
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy.orm import sessionmaker

Base = declarative_base()

class Customer(Base):
    __tablename__ = 'customer'
    id = Column(Integer, primary_key=True)
    name = Column(String)

    billing_address_id = Column(Integer, ForeignKey("address.id"))
    shipping_address_id = Column(Integer, ForeignKey("address.id"))
    billing_address = relationship("Address", foreign_keys=[billing_address_id])
    shipping_address = relationship("Address", foreign_keys=[shipping_address_id])
    #until here this is the example vannilla
    addresses = relationship("Address")

class Address(Base):
    __tablename__ = 'address'
    id = Column(Integer, primary_key=True)
    street = Column(String)
    city = Column(String)
    state = Column(String)
    zip = Column(String)
    #until here this is the example vannila
    customer_id = Column(Integer, ForeignKey("customer.id"))
    customer = relationship("Customer", foreign_keys=[customer_id], back_populates="addresses") 

if __name__ == "__main__":
    engine = create_engine('sqlite:///:memory:', echo=True)
    Base.metadata.create_all(engine)
    Session = sessionmaker(bind=engine)
    session = Session()
    c1 = Customer(name = "customer1")
    session.add(c1)
    #a1 = Address(street="streetA1", city="cityA1", state="stateA1", zip="zipA1") #this is according the example
    a1 = Address(street="streetA1", city="cityA1", state="stateA1", zip="zipA1", customer = c1) #this would be awsome
    session.add(a1)
    session.commit()

    print([x.id for x in session.query(Customer).all()])

AmbiguousForeignKeysError：无法确定连接条件

0 个答案: