SQLAlchemy 一个映射类中的多个外键到同一主键

我正在尝试设置一个 postgresql 表，该表有两个外键指向另一个表中的相同主键。

当我运行脚本时出现错误

sqlalchemy.exc.AmbigouslyForeignKeysError：无法确定关系 Company.stakeholder 上父/子表之间的联接条件 - 有多个外键路径链接这些表。指定“foreign_keys”参数，提供应被视为包含对父表的外键引用的列的列表。

这就是确切的错误SQLAlchemy 文档然而，当我复制他们提供的解决方案时，错误并没有消失。我可能做错了什么？

#The business case here is that a company can be a stakeholder in another company.
class Company(Base):
    __tablename__ = 'company'
    id = Column(Integer, primary_key=True)
    name = Column(String(50), nullable=False)

class Stakeholder(Base):
    __tablename__ = 'stakeholder'
    id = Column(Integer, primary_key=True)
    company_id = Column(Integer, ForeignKey('company.id'), nullable=False)
    stakeholder_id = Column(Integer, ForeignKey('company.id'), nullable=False)
    company = relationship("Company", foreign_keys='company_id')
    stakeholder = relationship("Company", foreign_keys='stakeholder_id')

我在这里看到过类似的问题，但是一些答案推荐一个使用primaryjoin但在文档中它指出你不需要primaryjoin在这个情况下。

尝试从foreign_keys中删除引号并使它们成为一个列表。来自官方文档Relationship Configuration: Handling Multiple Join Paths

0.8版本更改：relationship()可以解决之间的歧义 国外重点目标的基础上foreign_keys单独论证； 这primaryjoin在这种情况下不再需要争论。

下面的独立代码适用于sqlalchemy>=0.9:

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

engine = create_engine(u'sqlite:///:memory:', echo=True)
session = scoped_session(sessionmaker(bind=engine))
Base = declarative_base()

#The business case here is that a company can be a stakeholder in another company.
class Company(Base):
    __tablename__ = 'company'
    id = Column(Integer, primary_key=True)
    name = Column(String(50), nullable=False)

class Stakeholder(Base):
    __tablename__ = 'stakeholder'
    id = Column(Integer, primary_key=True)
    company_id = Column(Integer, ForeignKey('company.id'), nullable=False)
    stakeholder_id = Column(Integer, ForeignKey('company.id'), nullable=False)
    company = relationship("Company", foreign_keys=[company_id])
    stakeholder = relationship("Company", foreign_keys=[stakeholder_id])

Base.metadata.create_all(engine)

# simple query test
q1 = session.query(Company).all()
q2 = session.query(Stakeholder).all()