On 7/4/15 3:56 PM, Fridtjof Mund wrote:
So far I have set up the following:
|classUser(Base):__tablename__ ='users'id
=Column(Integer,primary_key=True)sent_messages
=relationship("Message",backref="sender")received_messages_association
=relationship(RecipientAssociation,backref="user")received_messages
=association_proxy("received_messages_association","message",creator=MediaAssociation.creator("user"))classGroup(Base):__tablename__
="groups"id =Column(Integer,primary_key=True)received_messages
=association_proxy("received_messages_association","message",creator=MediaAssociation.creator("group"))classRecipientAssociation(Base):__tablename__
="recipient_associations"id
=Column(Integer,primary_key=True)@classmethoddefcreator(cls,discriminator):"""Provide
a 'creator' function to use with the association
proxy."""returnlambdarecipient:RecipientAssociation(recipient=recipient,discriminator=discriminator)discriminator
=Column(String)"""Refers to the type of
recipient."""@propertydefrecipient(self):"""Return the recipient
object."""returngetattr(self,self.discriminator)|
This works fine for a one-to-one i have in the same project
(user/group with a picture, with uselist=False on backref), and it's
from an article zzzeek wrote on his blog. See the original source here
<http://techspot.zzzeek.org/files/2007/discriminator_on_association.py>.
Is there a better way to do this at all, and if there is not, what is
missing here for this to work? Am I completely thinking in the wrong
direction?
this is only a fragment (what's "Message"? What are the subtypes we're
dealing with?) so I don't really know what the goal is, that said the
2007 article was converted to an updated and enhanced series of examples
at
http://docs.sqlalchemy.org/en/rel_1_0/orm/examples.html#module-examples.generic_associations.
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