Thank you! You are not an SQL alchemist, you are a SQL Wizard! Thank you again!
For bonus points, an order by is possible on the discriminator like objects are returned consecutively: poly = with_polymorphic( AddressAssociation, [Customer.assoc_cls, Supplier.assoc_cls], aliased=True) eager_addresses = session.query(Address).options( joinedload(Address.association.of_type(poly)).joinedload( poly.CustomerAddressAssociation.parent), joinedload(Address.association.of_type(poly)).joinedload( poly.SupplierAddressAssociation.parent), ).order_by(poly.discriminator.desc(), poly.id) On Monday, November 24, 2014 4:04:41 PM UTC-8, Michael Bayer wrote: > > > On Nov 24, 2014, at 5:16 PM, Michael Bayer <mik...@zzzcomputing.com > <javascript:>> wrote: > > > On Nov 24, 2014, at 12:31 PM, Michael Bayer <mik...@zzzcomputing.com > <javascript:>> wrote: > > > On Nov 24, 2014, at 1:00 AM, Victor Reichert <vfr...@gmail.com > <javascript:>> wrote: > > I've taken another look at trying to eager load the address.parent. Is it > possible to do that? > > > Unfortuntately not really. It should be in theory but I’m not able to > work out an eager load that goes to both Customer and Supplier in terms of > AddressAssociation at the same time. I can get the query to render just > fine but the eager-targeting logic at the moment doesn’t seem to know how > to be told to go to two separate subclasses of a base class at the same > time. There’s probably improvements yet to be made in eager loading to > support this case better, e.g. this is a bug, but I’ve wrestled with it for > about an hour and I’m out of time on it for now, sorry. Even if it > works, the query is very unpleasant to look at :) If I get it working > later I’ll send it out. > > > OK here we go, the limitation is that the of_type() modifier is only > recognized along a particular path once. So to get over this we can use a > with_polymorphic(): > > > good news, i whacked that limitation in the latest master for 1.0. so > when 1.0 is released (in some months), you can do: > > eager_addresses = session.query(Address).options( > joinedload( > Address.association.of_type(Customer.assoc_cls)).joinedload( > Customer.assoc_cls.parent), > joinedload( > Address.association.of_type(Supplier.assoc_cls)).joinedload( > Supplier.assoc_cls.parent), > ) > > this will behind the scenes build up that with_polymorphic() thing for you. > > > > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.