Processing changes to the master data model

Question

I know that if you change the Core Data model and you run the application earlier on the old model, you will get the Persistent Store message. How would you deal with changes to the Core Data model so as not to get this error? Is there a way to update the old model so that data already saved is not lost?

Answer 1

If 10.6 is the base OS, you can use lightweight migration , in particular NSInferMappingModelAutomaticallyOption .

The article I wrote is similar and useful if 10.6 is not your base OS.

Answer 2

Core Data comes with a built-in mechanism for handling changes to your model.
See the "Versioning and Data Conversion Programming Guide for Master Data" section for details .