Question

I have several models inheriting from a base model.
The fields in the base model are needed rarely, but Django keeps doing complex inner joins to retrieve those fields whenever I use any of the inherited models.
How can I tell Django to avoid this ? I only need the fields in this model rarely.

Note: maybe only(..) would work(I didn’t check), but I would need to add it in many places in the code..

Answer 1

Use abstract model inheritance.

In short, setting abstract = True in the base class’ meta, makes Django using abstract inheritance, meaning each derived model will contain a copy of all the fields defined in the base model.

By the way, one of the Django’s maintainers, Jacob Kaplan-Moss has quite a strong opinion against concrete inheritance,

model inheritance also offers a really
excellent opportunity to shoot
yourself in the foot: concrete
(multi-table) inheritance

and again:

I’d strongly suggest that Django users
approach any use of concrete
inheritance with a large dose of
skepticism.

Personally, I have never had to use model inheritance at all; however, after reading that blog entry, I am quite convinced in trying to avoid concrete inheritance as much as possible.