问题
I've been searching around and let me get this straight, every time I change the attributes of my entities, I need to create an entirely new version of my model? I understand that the SQLite database is now out of sync with my data model, but can't I just delete the sql files and re-run my simulator? This is what I've been doing, but it doesn't seem to be working.
回答1:
You are correct, any changes to the core data model must be made in a new core data model version. You can avoid having to do this for development builds by resetting content and settings in the simulator, or deleting the old app version on a device before installing. For store builds though, you must correctly manage your model versions so that user's will have their persistent store properly migrated to a new store with the new model. Versioning is required so that lightweight migrations can be performed, without you having to write custom migration code. If you don't want to version your model, you are bound to writing code to properly migrate your entities. This can be a lot of work and difficult to maintain, you'd rather use lightweight migration and versioning.
来源：https://stackoverflow.com/questions/20364660/modifying-the-core-data-model-requires-new-version-every-time