I've got an app-architecture question, and I'm working with an older code base so bear with me.

We have a Theater object that represents a row in our database with a unique field, theaterId. As our app is pretty large, we have several pages that could instantiate an instance Theater after a request to our backend, and that new instance of Theater could have the same theaterId as another instance that is currently in memory elsewhere in the app. (i.e. theaterOnPageA == theaterOnPageB)

Based on the constraints of having to modify a large codebase that is split between Objective-C and Swift, I am currently trying to keep these instances in sync using NotificationCenter to publish notifications whenever an instance of Theater is updated, however, this has been less than ideal and requires a lot of cognitive overhead to debug.

I was wondering if this was a common problem throughout iOS apps that could be solved with a tried and tested architectural pattern?