executeFetchRequest:error: A fetch request must have an entity

Question

I had a project that was working fine. It had "Core Data" checked, and had the data model all set up. I only started adding a couple entities and properties tonight. When I try to run my app now, it won't even load. It just crashes on me.

Here's the error:

'NSInvalidArgumentException', reason: 'executeFetchRequest:error: A fetch request must have an entity.'

I'm really scared because I don't have a backup of this and if I can't get it working I don't know what I'll do. :)

Thanks in advance!

EDIT: I got fed up with my data, so I just copied a new blank xcdatamodel to my project and I'm going to start fresh. Thanks for the help!

Spancake

You need to post the relevant portions of the code. – Pickle

The code around your executeFetchRequest:error: call would be very helpful in understanding what your issue is. – Skim

You may be fetching the wrong entity from the coredata .. may be a typo at NSEntityDescription *entity = [NSEntityDescription entityForName:@"CHECK_HERE" inManagedObjectContext:managedObjectContext]; – Capacitate

Answer 1

It seemed as if my data got corrupted, so I deleted my data model and the database in the iPhone simulator, and started fresh.

Spancake

yeah, don't forget to delete the app from the simulator! – Brodeur

Answer 2

My issue is I didn't use the same name for Entity and Class. Trivial solution to fix it is by giving them the same name.

Sororate

is it a trivial solution? You can simply modify Default configuration (mapping: entity -> class) in data model. – Mobility

Answer 3

If you are using MagicalRecored with Swift:

Make sure you use @objc directive in the Swift NSManagedObject subclass to make the class accessible to Objective-C code from the MagicalRecord library

@objc(MyEntity)
class MyEntity: NSManagedObject {
    @NSManaged var myAttribute: Int16
}

Weir

Thanks! The entity file will get overwritten anytime you recreate the NSManagedObject subclass though. Is there a better way to do it than manually adding that line each time? – Executor

app crash in iOS 9.3 but working with iOS 10.3 when i add @objc(MyEntity) as suggested it work on iOS 9.3 but app crash on iOS 10.3 any idea why it crash? – Revolver

Answer 4

After searching all over for a solution, what fixed it for me was doing a Clean/Build in Xcode.

Product->Clean, Product->Build, then try running it.

Byelostok

I both deleted the app in the Simulator, and did Clean/Build. Same problem, so this did not fix the issue for me. I do not want to delete and recreate a complex data model. So, how to correct the issue non-destructively? – Fraise

Why the down-vote, @JayImerman? I'm sorry that my answer didn't work for you, but that doesn't mean you should down-vote it. Did you try a "Reset Content and Settings" in the simulator? Does it work on a real device? – Byelostok

Answer 5

I had the same error.

For me, it is because I have added a new Model Version, but I did not set it as "Current Version". Careless me! To fix, select the xcdatamodel, click Design > Data Model > Set Current Version. The xcdatamodel file will then have a green tick.

Hopes that helps.

Kun

Answer 6

Also, make sure that your .xcdatamodeld file is in the "Copy Bundle Resources" phase of your Build Phases.

Chief

Answer 7

Here's what fixed it for me:

As I was converting to Swift 3, Xcode was giving me an error when declaring a new NSFetchRequest, saying that it needed a type. After adding the type, I did what anyone else would have assumed; if the request is typed, why specify an entity name? So, I removed it.

It actually was my mistake.

Swift 2.2:

let request = NSFetchRequest(entityName: "MyEntity")

When I first converted to Swift 3:

let request = NSFetchRequest<MyEntity>()

That was giving me an error. I ended up with this:

let request = NSFetchRequest<MyEntity>(entityName: "MyEntity")

And everything works fine. Personally, I'm not sure why it needs to have an entity name specified, if you're typing the request. Maybe they'll update that at some point (I hope)

Chicken

Man thank you, you saved my day after searching the whole internet up and down. I wish I could upvote you 100 times! Still a valid solution in 2022 using SwiftUI by the way. – Afferent

Answer 8

i found this solution in the apple develper forum and it was exactly my problem!

the solutions is that the context must be defined inside the struct App. not in the environment parameter

import SwiftUI
@main
struct CoreDataDemoApp: App {
    
    private let context = CoreDataStack.context. 
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(\.managedObjectContext, context)
        }
    }
}

Soule

it says Aug 15, 2020 – Soule

Answer 9

Check if,

• the entity is present in the xcdatamodel file.
• entity name used are same.

Bamboozle

Answer 10

If you are using Swift 3 and Core Data's new stack syntax:

var persistentContainer: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "MyAppModel")
    container.loadPersistentStores(completionHandler: {
        (storeDescription, error) in
        if let error = error as NSError? {
            fatalError("Unresolved error \(error), \(error.userInfo)")
        } else {
            print(storeDescription)
        }
    })
    return container
}()

Then you should be using this fetch syntax:

let request: NSFetchRequest<Client> = Client.fetchRequest()

I had this error on the first fetch after app launches when using different variations:

let request: NSFetchRequest<NSFetchRequestResult> = Client.fetchRequest()

let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Client")

Rattlesnake

Answer 11

I did stumble across the same precise error upon taking my first steps into Core Data (and iOS 11 and Swift 4). I started off a book (sixth edition meant to target Swift 4 but presumably including some legacy stuff).

As suggested in the book my code was:

let fetchRequest = NSFetchRequest<ReminderData>()
let entity = ReminderData.entity()
fetchRequest.entity = entity
do {
    let rows = try managedObjectContext.fetch(fetchRequest)
} catch {
    fatalError("Unresolved error")
}

It turned out that all I got from ReminderData.entity() is nil. Not sure if I did something wrong when setting up the data model or ... Apple's docs say that NSManagedObject.entity() must not be overwritten?

Long story short, the Codegen file ReminderData+CoreDataProperties.swift did include the solution:

@nonobjc public class func fetchRequest() -> NSFetchRequest<ReminderData> {
    return NSFetchRequest<ReminderData>(entityName: "ReminderDB")
}

which was all I had to use to end-up with a proper NSFetchRequest, no fiddling with the NSEntityDescription, problem gone!

let fetchRequest = NSFetchRequest<ReminderData>(entityName: "ReminderDB")
do {
    let rows = try managedObjectContext.fetch(fetchRequest)
} catch {
    fatalError("Unresolved error")
}

Cataphyll

Or let fetchRequest: NSFetchRequest<ReminderData> = fetchRequest() with no need to type a name of the entity explicitly (by using that function which you mentioned in Codegen file ReminderData+CoreDataProperties.swift) – Amygdalate

Answer 12

I built clean, and that didn't fix it. Then I deleted the app, and that didn't fix it. Then I built clean and deleted the app AT THE SAME TIME, and that fixed it.

Guanaco

Answer 13

In my case, it was because this dropdown was not set to "Current Product Module" in the Data Model Inspector in Xcode (13.4.1):

Once I set that, it stopped crashing.

Hope this helps!

Cyanate

Answer 14

Just add the same problem. I copied all my entities. Deleted the data model, recreated an empty one and pasted the entities back into the new data model. Solved my issue.

Haydenhaydn

Answer 15

First I downloaded the app's data through the Organizer (to see what was happening) and noticed that it offered me to save it under a previous project name. This puzzled me. So I exited XCode 4.6.1, deleted the app (and its data) from my iPhone, and came back.

This time I got an error saying Cannot create an NSPersistentStoreCoordinator with a nil model. So I looked into the AppDelegate.m file and changed the URLForResource in the - (NSPersistentStoreCoordinator *) persistentStoreCoodinator method. It was set to the name of my app, and I changed it to 'Model' so as to match the name of my Model.xcdatamodeld.
It's working now.

Maller

Answer 16

This happened to me when I was fetching from the wrong database. My application has 3 sqlite databases, and of course 3 ManagedObjectContext instances. Well I was submitting the wrong ManagedObjectContext to a method asking it to query a table that didn't exist in the ManagedObjectContext I submitted. After using the correct ManagedObjectContext, all was good.

Morphosis

Answer 17

I think the original question/problem, and also the issue that most of these answers fixes (just in different ways) is just a real simple one:

Anytime you modify your core data (like adding an entity as you mention), you either have to delete all existing data (if you haven't published your app yet), or add a new version to your model.

Just thought I would post this answer, even though this is an older question, because this answer seems pretty obvious and so far hasn't been discussed in any of the questions or comments I read above.

Treulich

Answer 18

You can also use setter method from CoraData ... Just do something like this...

On your CustomCoreDataManager.m

import "ObjectiveRecord.h" call init method like this

(instancetype)init {

self = [super init];

if (self) {

[[CoreDataManager sharedManager] setModelName:@"YourModelName"]; }

return self; }

Hope this helps to someone...

Unquestionable

Answer 19

Maybe you are trying to load a Database from a different/the wrong bundle? For instance from or within a Framework?

I had this issue and solved it by loading the DB from the bundle of the related Framework. And then it all worked fine!!

Swift 4 + MagicalRecord:

let frameworkBundle = Bundle(for: AClassFromTheFramework.self)
let managedObjectModel = NSManagedObjectModel.mergedModel(from: [frameworkBundle])
MagicalRecord.setShouldAutoCreateManagedObjectModel(false)
NSManagedObjectModel.mr_setDefaultManagedObjectModel(managedObjectModel)
MagicalRecord.setupCoreDataStack(withAutoMigratingSqliteStoreNamed: "db.sqlite")

And voila !

Radiocommunication

Answer 20

I faced same issue, actually i was calling MyEnty instead of MyEntity so please re-check what names you have given to your entities and call the same and also check whether you are calling same attributes that you have defined like name

Caia

Answer 21

• having an entity in the xcdatamodel
• using the entity for some time in the project
• later I have removed the entity from the code, but not from the xcdatamodel.
• solution: removed the unsued entity also from the xcdatamodel file

Lend

Answer 22

This error occurred for me when I accidentally initialized my Core Data stack twice.

Prominence

Answer 23

If you are using in-memory store (/dev/null), the entities will not be loaded or created. @FetchRequest will cause this error if you do not create and save some entities.

Nonproductive

Answer 24

I accidentally added the new entity to the previous version. then added it to the current version and deleted the previous one.

and had all this trouble. I tried cleaning, etc... still got the error.

in the end I quit Xcode and relaunched. it all worked... sigh.

Arabela