On Sep 2, 2010, at 8:59 AM, Julien Cigar wrote: > Hello, > > Another quick question on .with_polymorhpic() .. :) > > When I use inheritance I always subclass a Query object per mapped (child) > class, for example : > > class QueryRoot(orm.Query): > > def available_to_all_children(self): > return self.filter(...) > > class RootModel(object): > > query = Session.query_property(QueryRoot) > > > class QueryChild(QueryRoot): > > def a_child_filter(self): > return self.filter(...) > > class ChildModel(RootModel): > > query = Session.query_property(QueryChild) > > > then the mappers: > > mapper(Root, table_root, > polymorphic_on=table_root.c.type_id > ) > > mapper(Child, table_child, > inherits=Root, > polymorphic_identity='child' > ) > > it works well, and the ability of sub classing a Query class is very elegant! > > The only "problem" is that when I use something like : > Root.query.with_polymorphic([Child]) I would like to be able to use > QueryChild filters (so be able to do something like > Root.query.with_polymorphic([Child]).a_child_filter()). Sounds logical > because Child columns will always be present in the result set (because of > the LEFT OUTER JOIN) > > How would you do that properly?
RootQuery is already a subclass, override with_polymorphic to look at the args and produce the kind of Query class you want. > > Wouldn't it be interesting to add an option to .with_polymorphic()? ummm this is all pretty Julien-specific stuff so far ... :) > > Thanks, > Julien > > > -- > No trees were killed in the creation of this message. > However, many electrons were terribly inconvenienced. > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To post to this group, send email to sqlalch...@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. > > <jcigar.vcf> -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@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.
