class Parent(Base):
__tablename__ = 'parent'
id = Column(Integer, primary_key=True)
children = relationship("Child", back_populates="parent")
class Child(Base):
__tablename__ = 'child'
id = Column(Integer, primary_key=True)
parent_id = Column(Integer, ForeignKey('parent.id'))
parent = relationship("Parent", back_populates="children")
1，ForeignKey参数中是表名，非模型名， 如是一对一关系，只需要在其中一个模型中配置外键即可
Could not determine join condition between parent/child tables on relationship User.Bonus - 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.
2，back_populates的值一定是在对应的模型中的属性，没有就会报
'One or more mappers failed to initialize - can\'t proceed with initialization of other mappers. Triggering mapper: \'mapped class User->bp_user\'. Original exception was: Mapper \'mapped class Bonus->bp_bonus\' has no property \'User\''
3，查询时不能你中有我，我中有你，会报
'Circular reference detected'
