Ah Thanks! A bit of a hack but certainly works for now. Thanks for helping out. Really appreciate it!
Jimmy Yuen Ho Wong On 10/1/12 3:31 AM, Michael Bayer wrote: > On Jan 9, 2012, at 11:19 AM, Michael Bayer wrote: > >> The first thing I note here is, if I were doing a model like this, I'd >> either use two different association tables between Product->Origin and >> Product->Food, or I'd make one relationship(), and handle the filtering in >> Python (which is essentially what you're wishing SQLAlchemy did here). The >> ORM wants to know about your table relationships which here is just >> A->assoc->B. All of the issues here, some of which I consider to be SQLA >> bugs anyway, would go away if you did it in that manner, subqueryloading >> would be efficient, etc. > > Here's an event that does what you need: > > from sqlalchemy.orm import attributes > from sqlalchemy import event > > class Product(Base): > > __tablename__ = "product" > > id = Column(Integer, autoincrement=True, primary_key=True) > > options = relationship(SearchOption, secondary=product_searchoption_table) > origin = relationship(OriginOption, uselist=False, > secondary=product_searchoption_table) > foods = relationship(FoodOption, > secondary=product_searchoption_table) > > @event.listens_for(Product, "load") > def mything(target, context): > if 'options' in target.__dict__: > attributes.set_committed_value( > target, 'foods', > [o for o in target.options if o.discriminator=='food'] > ) > origin = [o for o in target.options if o.discriminator=='origin'] > attributes.set_committed_value( > target, 'origin', > origin[0] if origin else None > ) > > # only 2 queries > for row in session.query(Product).options(subqueryload(Product.options)): > print row, row.origin, row.foods > > if I added an onload event for individual relationship attributes that would > make this event a little more targeted. > > > > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
