Reputation: 11053
I have an app on the market which has just one object instance a1
of class A in core data.
In the new version I now need 2 instances b1, b2
of a new class B,and 2 instances c1, c2
of new class C
. here b1
and c1
get most data from old a1
while b2
and c2
have to be created but left empty - so do not get data from the old core data object.
All tutorials and descriptions elaborate on data transformation old -> new, but in my case its about this migration from old data to new including creating the new empty objects.
What would be the correct way to do this, since "typical migration" does not really cover this case?
I did the same in Android with my database, there it is really easy but I am not sure how to "press" my problem into core data migration scheme.
many Thanks!
Upvotes: 0
Views: 109
Reputation: 21902
You have to create a custom migration policy. Use this post as a guideline to get started and get a good starting point for researching the docs.
Core Data versioning and migrating with custom policy
Upvotes: 1