iOS Core data migration to another machine

I received the source for an application from a guy to make a few changes in the app. The data model version was, say, App3. I had to add about 3-4 more data model versions in the process. So the active model version when I sent him was App7

I built the project (it was running properly on my mac) I sent him the zip and when he ran, he got the error "Can't find model for source store" I had him create the latest data model again, based on the data model App3 and make it the same as App7 and set it as the current version.

He still has the error and I can't figure out why? Are the intermediate data model version causing issues? Is it required to delete the sqlite file in the application support->iphone simulator folder? I am all over the place with this. Please help!

Answers


You need to have both model files and have some sort of versioning in place. The new model that you made will no longer work with his data file unless you specify to Core Data that you want it to update the data.

Versioning isn't that easy, but if your changes are small enough, you might be able to get away with automatic versioning. Read the guide and see:

http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CoreDataVersioning/Articles/Introduction.html


In my understanding, it will. But really that is not the thing to do if ultimately the versioning is going to happen on existing live apps too.


For the light-weight migration to work, you need to send him all the intermediate versions of the model as well since the migration takes place stage by stage through all versions.

And you have to make sure that you have made no modification (even accidentally) to the base version App3.


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