Core Data Relationships and GUI Development
1. Data Migration
When dealing with data migration, the system attempts a lightweight migration by inferring the mapping. If the mapping can’t be inferred, the process stops, and an error is returned. For example, the error message “The managed object model version used to open the persistent store is incompatible with the one that was used to create the persistent store” will be presented. However, in some cases, the mapping can be inferred, and the lightweight migration is performed automatically. The old data file is first backed up in case something goes wrong. This automatic procedure ensures that users don’t need to worry about importing or converting data when running a new version of the app.
超级会员免费看
订阅专栏 解锁全文
32

被折叠的 条评论
为什么被折叠?



