Chapter 6: Error with complex mapping model

📚 Official Books Core Data by Tutorials
1

Chapter 6 is giving me lots of headaches. I still didn’t figure out what’s wrong with my code when performing the manual migration, so I decided to move on and use the provided V3 project as a starting point to continue with the chapter.

After implementing the complex mapping model I get an error:

Thread 1: Fatal error: Unresolved error Error Domain=NSCocoaErrorDomain Code=134110 “An error occurred during persistent store migration.” UserInfo={NSUnderlyingException=Couldn’t create mapping policy for class named (UnCloudNotes.AttachmentToIimageAttachmentMigrationPolicyV3toV4)}

Screen Shot 2020-05-01 at 6.43.18 PM

UnCloudNotes.zip (124.4 KB)

I find the chapter very confusing. Some screenshots are missing and I noticed the instructions never mention to change Codegen to Manual/None too match the screenshots.

Perhaps this chapter needs a review?

2

@jvantoor Please check out the update version of the book when you get a chance:

https://store.raywenderlich.com/products/core-data-by-tutorials

I hope it helps!

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