Re: polymorphism and abstract classes

2008-08-22 Thread Shay
Hi Kip, Thanks for your help with this. :) MTI is meant to be Multi-Table Inheritance, sorry. I copied the reference from other Django related docs. :) About using that generic_relations example, it's hard to explain without diagrams but I'll give it a try... Based on that example:

Re: polymorphism and abstract classes

2008-08-21 Thread Kip Parker
Though I'm not sure what MTI is (Google suggest "Massage Training Institute", but that can't be right), what you're trying to do seems well within Django's capabilities. Generic relations allow you to create foreign keys to any other object, so you'd have a Generic Foreign Key in your enclosure,

Re: polymorphism and abstract classes

2008-08-20 Thread Shay
Hi, Thanks for the tip, I found Generic Relations and GenericForeignKey shortly after I posted this and you confirmed I was looking in the right place. :) It seemed a better idea to make Animal abstract since I don't want it to be able to be instantiated on its own. ZooEnclosure should only be

Re: polymorphism and abstract classes

2008-08-20 Thread Kip Parker
Maybe have a look at generic relations? http://www.djangoproject.com/documentation/models/generic_relations/ You could also use multi-table inheritance rather than abstract classes, then use the parent class Animal as the key in ZooEnclosure. Abstract classes can't exist on their own, which I

polymorphism and abstract classes

2008-08-19 Thread Shay
Hi, I'm rather new to Django, so please bear with me. :P I've been trying to figure out how to implement the following in models: class: Animal (abstract class) ... class: Zebra (extends Animal) ... class: Snake (extends Animal) ... class: ZooEnclosure String enclosureName Animal