sqlalchemy - OneToOne Relationship with a foreign key on both sides

Question

How can I define a OneToOne-relationship between two tables and have a foreign key on both sides? I know that it is redundant.

class A(Base):
  __tablename__ = 'A'
  id = Column(Integer, primary_key=True)
  b_id = Column(Integer, ForeignKey('b.id'), unique=True, nullable=False)
  b = relationship("B", uselist=False, back_populates="a")

class B(Base):
  __tablename__ = 'B'
  id = Column(Integer, primary_key=True)
  a_id = Column(Integer, ForeignKey('a.id'), unique=True)
  a = relationship("A", uselist=False, back_populates="b")

This results into an error:

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

I found this duplicate to my question: SQLAlchemy one-to-one, store foreign key in each table? but the accepted answer is not an answer to the question. I only tells that normaly only one key is needed.

question from:https://stackoverflow.com/questions/65869224/onetoone-relationship-with-a-foreign-key-on-both-sides

Answer 1

Waitting for answers