Realm does not support subclassing from RLMObject subclasses

[mergesort]

When doing OO programming, it's quite a common behavior to have a base super class which can have properties such as created_at, updated_at, or whatever your all subclassed models will need. When using a common ORM like ActiveRecord, all of the objects inherit from ActiveRecord::Base, and the model often has a has_one relationship with what it's "inheriting", it's not really an expected behavior in the functionality that Realm is attempting to provide.

If the goal of Realm is to abstract away the database side of your code and treat persisted models as regular models, then it would make sense to support direct subclassing of objects which inherit from RLMObject. Besides clarity, this would have the added benefit of lowering the barrier for someone who to add persistence into a project which does not have it, without re-architecting the models, in the same way that CoreData allows.

[timanglade]

Thanks for the write-up @mergesort. We definitely want to allow something like this, be it via inheritance or via composition. It’s hard to do well (read: while maintaining performance with millions of objects composed from a complex hierarchy of inheritances), but we have a few ideas we’re working on…

[alazier]

This is now supported in master with #940