On 2/14/2014 11:50 AM, Michael Bayer wrote:
On Feb 14, 2014, at 12:46 PM, Michael Hipp <mich...@redmule.com> wrote:
On 2/13/2014 11:45 AM, Michael Bayer wrote:
So for "children" above you need to spell out primaryjoin completely which is
primaryjoin="and_(Animal.sire_id == Animal.id_, Animal.dam_id == Animal.id)".
Thought I was on the right track but now getting the exception below. Here's
the model:
class Animal(Base):
__tablename__ = 'animals'
id_ = Column(Integer, primary_key=True)
sire_id = Column(Integer, ForeignKey('animals.id_'))
dam_id = Column(Integer, ForeignKey('animals.id_'))
sire = relationship('Animal', foreign_keys=[sire_id])
dam = relationship('Animal', foreign_keys=[dam_id])
pjoin = 'and_(Animal.sire_id == Animal.id_, Animal.dam_id == Animal.id_)'
children = relationship('Animal', foreign_keys=[sire_id, dam_id],
primaryjoin=pjoin)
So I attempt to put in the first object, which is to be a bit special:
unknown = Animal(id_=0)
db_session.add(unknown)
unknown.sire = unknown # <- get exception here
unknown.dam = unknown
db_session.commit()
TypeError: Incompatible collection type: Animal is not list-like
unknown.sire shows to contain [] so it evidently wants a list of sires? That's
not what I had in mind for the above model. Any help?
well here we're doing a self-referential relationship so in order to make a
many-to-one self ref, as someone else mentioned you need remote_side=sire_id
background:
http://docs.sqlalchemy.org/en/rel_0_9/orm/relationships.html#adjacency-list-relationships
Changed model to read:
sire = relationship('Animal', foreign_keys=[sire_id], remote_side=sire_id)
Same exception: TypeError: Incompatible collection type: Animal is not list-like
Also tried it with remote_side=[sire_id], same exception
Also tried putting it on the 'children' relationship, same exception:
children = relationship('Animal', foreign_keys=[sire_id, dam_id],
primaryjoin=pjoin, remote_side=[sire_id, dam_id])
Thanks,
Michael
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