CODEWITHSUNDEEP
ioscore-data
Nan
Nan

Reputation: 524

iOS 13, CoreData crash regarding transform property

I am trying to load file from Core Data as I did before. My CoreData stack as follows:

import Foundation
import CoreData

class SaveData:NSObject {



lazy var persistentContainer: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "DataModel")
    container.loadPersistentStores(completionHandler: {
    storeDescription, error in
    if let error = error {
        fatalError("Could load data store: \(error)")     }   })
    return container }()


lazy var managedObjectContext: NSManagedObjectContext = persistentContainer.viewContext

}

My DataModel: enter image description here

I have no trouble of saving data when saving function is trigger. But having trouble of fetching data. My fetch method like this:

var saveData = SaveData()

var locations = [Location]()

override func viewDidLoad() {
    super.viewDidLoad()

    let fetchRequest = NSFetchRequest<Location>()   // 2
    let entity = Location.entity()
    fetchRequest.entity = entity   // 3
    let sortDescriptor = NSSortDescriptor(key: "date", ascending: true)
    fetchRequest.sortDescriptors = [sortDescriptor]

    do {
        locations = try saveData.managedObjectContext.fetch(fetchRequest)
    } catch {
        fatalCoreDataError(error)
    }

}

When fetching the data from CoreData, app crashes. The debugs area says: 2019-10-02 20:44:29.780267+0800 MyLocation[20870:2214196] [error] error: No NSEntityDescriptions in any model claim the NSManagedObject subclass 'Location' so +entity is confused. Have you loaded your NSManagedObjectModel yet ? CoreData: error: No NSEntityDescriptions in any model claim the NSManagedObject subclass 'Location' so +entity is confused. Have you loaded your NSManagedObjectModel yet ? 2019-10-02 20:44:29.780387+0800 MyLocation[20870:2214196] [error] error: +[Location entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass CoreData: error: +[Location entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass 2019-10-02 20:44:29.789644+0800 MyLocation[20870:2214196] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'executeFetchRequest:error: A fetch request must have an entity.'

I have tried the solution I can find, nothing works at the moment. How to resolve this issue? Thanks in advance.

Upvotes: 1

Views: 1268

Answers (1)

jawad
jawad

Reputation: 825

I've fixed this issue before.

First I was declaring a method named fetchRequest() on the managed object like that:

  extension OrderType {
        @nonobjc public class func fetchRequest() -> NSFetchRequest<OrderType> {
            return NSFetchRequest<OrderType>(entityName: "OrderType")
        }
        @NSManaged public var orderType: String?
        @NSManaged public var orderTypeId: Int32
        @NSManaged public var order: NSSet?
    }

The app was crashing on this line:

let itemCount = try managedObjectContext.count(for: OrderType.fetchRequest())

In order to fix this crash I've changed the code to:

let fetchRequest = OrderType.fetchRequest()
let itemCount = try managedObjectContext.count(for: fetchRequest)

the crash disappeared! hope it works with you too ^^

Upvotes: 1

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