Migrating from one Core Data model to another

Question

I have a first app (App1) which has a Core Data data model (model1). I have completely rewritten the app (app2) in a separate Xcode project and it has a new data model (model2).

I am trying to understand how I can migrate the persistent store of app1 and model1 to app2 and model2 so that a user's data is transferred over.

There are some differences between model1 and model2 (entity/attribute/relationship names etc) but I think these can be dealt with via lightweight migration. Therefore, currently my main problem is working out how to link model2 to model1 so that app2 can attempt the migration.

I have tried copying the model1.xcdatamodel file into the new project for app2 and then versioning this model1 with a new version corresponding to model2.

The app launches and doesn't crash, but none of the data is transferred. I have included the persistent store options as follows:

let options = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true]

How does app 2 access the persistent store (or the underlying SQLite db) in app 1 in your current solution? — Joakim Danielson, Apr 15 '23 at 16:58
Does app 2 have the same bundle ID as app 1 or a new bundle ID? — Tom Harrington, Apr 15 '23 at 23:57
Both apps have the same bundle ID, so my understanding is that app2 would be seen as a new build of app1. — J.Cosgrove, Apr 16 '23 at 08:23
It should be treated as the same app. Everything you've described sounds OK. The question needs more detail to lead to an answer. — Tom Harrington, Apr 17 '23 at 16:49

Migrating from one Core Data model to another

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