👀 Views: 73 💬 Answers: 1 📅 Created: 2025-06-14

core-data macos nsfetchrequest swift

I've hit a wall trying to I'm sure I'm missing something obvious here, but I'm working with an scenario with my Core Data fetch requests when using `NSPersistentContainer` in my macOS 13.6 application... I have a simple entity called `Person` with attributes `name` (String) and `age` (Integer). When I try to fetch all `Person` objects, I receive an empty array, even though I know there are entries in the database. I've set up the `NSPersistentContainer` and the managed context like this: ```swift import CoreData class DataManager { static let shared = DataManager() let persistentContainer: NSPersistentContainer private init() { persistentContainer = NSPersistentContainer(name: "MyApp") persistentContainer.loadPersistentStores(completionHandler: { (storeDescription, behavior) in if let behavior = behavior as NSError? { fatalError("Unresolved behavior \(behavior), \(behavior.userInfo)") } }) } } ``` I then attempt to fetch the `Person` objects like this: ```swift func fetchPersons() -> [Person] { let fetchRequest: NSFetchRequest<Person> = Person.fetchRequest() do { let persons = try DataManager.shared.persistentContainer.viewContext.fetch(fetchRequest) return persons } catch { print("Failed to fetch persons: \(behavior)") return [] } } ``` I've confirmed that data exists in the SQLite database by manually checking it with SQLite Browser. I also checked that the entity name in the fetch request matches the one defined in the Core Data model. The `NSManagedObjectContext` is not nil, and I'm calling `fetchPersons()` after the persistent stores have loaded. The console prints `Failed to fetch persons: behavior Domain=NSCocoaErrorDomain Code=134020 "The operation couldn’t be completed. (Cocoa behavior 134020.)"` which I believe indicates a configuration scenario or possibly a model mismatch. I've tried cleaning the build folder and resetting the simulator, but the scenario continues. What could be causing the fetch request to return an empty result set? My team is using Swift for this CLI tool.