SQLAlchemy Inheritance and backrefs #89
Description
If I define an inherited relationship (joined-table in this case) in SQLAlchemy, the backref is not being properly understood by ColanderAlchemy.
In my contrived example there is Person, which is sub-classed in Gamer. Gamer can have some Scores associated with it.
class Person(Base):
__tablename__ = 'person'
satype = Column(String(50))
__mapper_args__ = {
'polymorphic_identity': 'person',
'polymorphic_on': satype
}
id = Column(Integer, primary_key=True)
name = Column(String(128))
surname = Column(String(128))
class Gamer(Person):
__tablename__ = 'gamer'
__mapper_args__ = {
'polymorphic_identity': 'gamer',
}
__colanderalchemy_config__ = {
'excludes': ['satype']
}
id = Column(Integer, ForeignKey('person.id'), primary_key=True)
high_score = Column(Integer)
class Score(Base):
__tablename__ = 'score'
id = Column(Integer, primary_key=True)
gamer_id = Column(Integer, ForeignKey('gamer.id'))
gamer = relationship('Gamer', backref='scores')
value = Column(Integer)This will serialize a Gamer to this:
{'high_score': <colander.null>,
'id': '1',
'name': u'Jayne',
'surname': u'Cobb'}
Which is not what I was expecting. The scores backref is being ignored.
Redefine Gamer to remove use of inheritance like so:
class Gamer(Base):
__tablename__ = 'gamer'
id = Column(Integer, primary_key=True)
name = Column(String(128))
surname = Column(String(128))
high_score = Column(Integer)and the result is:
{'high_score': <colander.null>,
'id': '1',
'name': u'Jayne',
'scores': [{'gamer_id': '1', 'id': '1', 'value': '1000'},
{'gamer_id': '1', 'id': '2', 'value': '2000'}],
'surname': u'Cobb'}
which is exactly what I was expecting.
Just for completeness I also tried redefining score to make use of Person instead of Gamer in its relation. This makes no difference:
class Score(Base):
__tablename__ = 'score'
id = Column(Integer, primary_key=True)
gamer_id = Column(Integer, ForeignKey('person.id'))
gamer = relationship('Person', backref='scores')
value = Column(Integer)Working example: https://gist.github.com/dpwrussell/f465aee4618580614f61
I think this must be a bug as I can't see why that would happen otherwise.
Cheers