> app_objects = managers.PolymorphicManager(Place, Restaurant, > ItalianRestaurant) > `` > > This also makes it explicit which classes are participating in a join, > rather than potentially joining a large number of installed model classes. >
Thus making it completely unnatural to inherit from a class that you didn't write your self - ie you must monkey patch in the manager, and then what kind of trouble do you get in when two apps by different users want to extend the same core class. Horrific. Coupling supertypes to subtypes is madness.... I think all that is needed here is education - it needs to be pointed out what the costs of subtyping are. One option would be to provide a method on managers to provide a "faster but broken" manager, ie joinless. It needs to have a name to suggest that it is not really recommended though, and should only be used if it actually has a beneficial performance impact...
