Question

I’ve been following the CS193p’s lectures on Core data and I’ve run into a problem when I’m inserting a new managed object.

The error is:

Terminating app due to uncaught exception ‘NSInternalInconsistencyException’, reason: ‘+entityForName: could not
locate an entity named ‘Card’ in this model.’

I’ve created the “Card” entity in my data model file. However I have a feeling it isn’t finding the data model file correctly, since removing that file all together give the same error. I’m wondering how I can find out whether it is due the UIManagedDocument object not finding the data model that is causing this error.

Here is what I’m doing in my controller class:

NSURL *docURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
NSURL *databaseURL = [docURL URLByAppendingPathComponent:@"Cards Database"];
self.cardsDatabase = [[UIManagedDocument alloc] initWithFileURL:databaseURL];

if (![[NSFileManager defaultManager] fileExistsAtPath:[self.cardsDatabase.fileURL path]]) {
    [self.cardsDatabase saveToURL:self.cardsDatabase.fileURL forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) {
        NSLog(@"Done");
    }];
} else if (self.cardsDatabase.documentState == UIDocumentStateClosed) {
    NSLog(@"Closed");
    [self.cardsDatabase openWithCompletionHandler:^(BOOL success) {
        if (success) {
            NSLog(@"Opened");
            [self addSampleData];
        }
    }];
} else if (self.cardsDatabase.documentState == UIDocumentStateNormal) {
    NSLog(@"Normal");
}


- (void)addSampleData
{
    NSManagedObjectContext *context = self.cardsDatabase.managedObjectContext;

    [context performBlockAndWait:^{
        Card *card = [NSEntityDescription insertNewObjectForEntityForName:@"Card" inManagedObjectContext:context];

        card.title = @"Test Title";
    }];

    [self.cardsDatabase saveToURL:self.cardsDatabase.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:^(BOOL success) {
        NSLog(@"Saved");
    }];
}

The error occurs on this line:

Card *card = [NSEntityDescription insertNewObjectForEntityForName:@"Card" inManagedObjectContext:context];

Answer 1

Try resetting the simulator(In device, remove the app), clean the build and run again. That should resolve most of the issues related to ‘could not locate entities’.