Core Data quiz

Test your Core Data knowledge with a free interactive quiz — 20 questions with answers and explanations. No signup needed to play.

What is the role of `NSPersistentContainer`?

1. What is the role of `NSPersistentContainer`?
2. Why does Core Data avoid loading an entire large dataset into memory when displaying, say, thousands of records?
3. What is `@FetchRequest` in SwiftUI, and how does it relate to Core Data?
4. What is a `NSFetchedResultsController` used for?
5. What does `viewContext` refer to on an `NSPersistentContainer`?
6. What does `NSBatchDeleteRequest` provide that a normal fetch-then-delete loop doesn't?
7. Why is it generally unsafe to pass an `NSManagedObject` fetched on one context/thread directly into another thread's work?
8. What happens if you call `context.save()` and it throws an error — what is a common cause?
9. What is the difference between a Core Data "attribute" and a "relationship" on an entity?
10. What is an `NSManagedObjectContext`?
11. What does `NSManagedObjectContext.mergePolicy` control?
12. What is a lightweight migration in Core Data?

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