Notes for iOS coredata application upgrade

If your app uses coredata technology, crash will occur when you modify the DB field and upgrade it to the new version. because only the application app is upgraded, the DB files in the update directory are not. If it is under development, you only need to install the deleate app again. If you upload the software to the appstore, you must be careful with it. apps that have not been processed by migrate will inevitably crash after the upgrade.

The required technologies are coredata versioning and migrate.

Http://developer.apple.com/library/ios/#documentation/cocoa/conceptual/CoreDataVersioning/Articles/vmLightweight.html

Http://iphonedevelopment.blogspot.com/2009/09/core-data-migration-problems.html

Http://mobile.tutsplus.com/tutorials/iphone/core-data_schema-versioning-and-lightweight-migrations/

Lightweight migrate only supports lightweight dB modifications, such as the insert/update/delete attributes. For tables, for more complex data migration, such as migrating a property * 30% to a new model, you mustMapping model