How to query abstract-class-based objects in Django?

Question

Let\'s say I have an abstract base class that looks like this:

class StellarObject(BaseModel):
  title = models.CharField(max_length=255)
  description = mod         


        

Answer 1

This is an example of polymorphism in your models (polymorph - many forms of one).

Option 1 - If there's only one place you deal with this:

For the sake of a little bit of if-else code in one or two places, just deal with it manually - it'll probably be much quicker and clearer in terms of dev/maintenance (i.e. maybe worth it unless these queries are seriously hammering your database - that's your judgement call and depends on circumstance).

Option 2 - If you do this quite a bit, or really demand elegance in your query syntax:

Luckily there's a library to deal with polymorphism in django, django-polymorphic - those docs will show you how to do this precisely. This is probably the "right answer" for querying straightforwardly as you've described, especially if you want to do model inheritance in lots of places.

Option 3 - If you want a halfway house:

This kind of has the drawbacks of both of the above, but I've used it successfully in the past to automatically do all the zipping together from multiple query sets, whilst keeping the benefits of having one query set object containing both types of models.

Check out django-querysetsequence which manages the merge of multiple query sets together.

It's not as well supported or as stable as django-polymorphic, but worth a mention nevertheless.