Python-сообщество

class A(Declarative):
    __tablename__ = u'a'
    id = Column(Integer, Sequence(u'a_id_seq'), primary_key=True, unique=True, nullable=False)
    title = Column(Unicode)
    b = Column(Integer, ForeignKey(u'b.id'), nullable=False, index=True)

class B(Declarative):
    __tablename__ = u'b'
    id = Column(Integer, Sequence(u'b_id_seq'), primary_key=True, unique=True, nullable=False)
    title = Column(Unicode)

[(<B object at 0x1>, <A object at 0x2>), (<B object at 0x1>, <A object at 0x3>), (<B object at 0x1t>, <A object at 0x4>)]

[(<B object at 0x1>, (<A object at 0x2>, <A object at 0x3>, <A object at 0x4>))]