I need to override library model field in Django. This model is integrated in that library and used there. The changes I need is to add a unique constraint to one of the model fields. But this is not the abstract model so I can't inherit this model as I understand.
The question: is there a way to override usual model field in Django without inheritance?
Not that I'm aware of. I'd be looking at modifying (forking) the "library" model, although there might be issues if it's proprietary 3rd party code for which you do not have source.
The usual thing against concrete inheritance is that it causes a new DB table to be created and thereafter, every query involves a join on a OneToOne field between the two tables. However, I'm wondering whether this happens if you merely add a constraint to an existing field. Might be worth investigating in detail.
Likewise, can you inherit merely to subclass the .save() method, and apply the equivalent to a constraint therein? This isn't bullet-proof, because it's enforced only by the saving of Django objects and can be overridden both by django bulk_update and by anybody accessing the DB table without Django. And again, does it end up creating and joining a second DB table even if it contains no fields at all (except a primary key).
Sorry, more questions than a proper answer. Maybe somebody knows these answers?
