Migrating coreData to a clean start

Question

I'm updating an app to a whole new version (remade). Everything is going to change to be faster and less bugy. As other post suggest I cannot create another version of the model since I don't have the app code to the previous version (I started a new project). All I have is the bundle identifier for it to be an update. I will use core data but I want to delete all the old models and old data for the users that are updating, as if they deleted the app and reinstall it. How do I achieve this? or there's no need to delete anything because is a different model? All i want is to prevent app crash on launch. thanks in advance.

Answer 1

If you tried to open the same persistent store file with a model that doesn't allow Core Data to make sense of it then you'd raise an exception. So probably all you need to do is use a different file — remember that you get to specify the on-disk location in addPersistentStoreWithType:configuration:URL:options:error: — for your persistent store and ask NSFileManager to delete the old one.

I don't think there's a penalty for asking to delete a file that already doesn't exist so no need for any particularly complicated logic. You'd just be duplicating what the file manager does internally anyway.

Alternatively, if you prefer to keep the same file, enclose your call to addPersistentStoreWithType:... in an @try/@catch block and in the @catch just delete the existing file and try the addPersistentStoreWithType:... a second time.