coredata- relationship failing to behave properly

Question

This is structure of coredata architecture.

After adding entries to 'Artists', using them to newly added 'Album' entries is working perfect.

But the problem is as shown in img- 2 & 3, after assigning the 'michael jackson' to 'Insomniac 2010' album & then adding the same artist to 'Baby ft ludacris' losing the reference from the album 'Insomniac'.

This is the code where I save the context in AlbumDetailViewController.h

- (void)EntityRecordstableview:(UITableView *)tableView didselectrowatindexpath:(NSIndexPath *)indexPath forentity:(id)entity
{
    Artist *selectedArtist = entity;

    UITableViewCell * cell = [tableView cellForRowAtIndexPath:indexPath];
    [cell setSelected:NO animated:YES];

    if ([self.pickedArtists containsObject:selectedArtist]) {
        [self.pickedArtists removeObject:selectedArtist];
        [cell setAccessoryType:UITableViewCellAccessoryNone];
        editingAlbum.artist = self.pickedArtists;
        [self saveTheContext:editingAlbum.managedObjectContext];
//        NSLog(@"%d",self.pickedArtists.count);
    }
    else {
        [self.pickedArtists addObject:selectedArtist];
        [cell setAccessoryType:UITableViewCellAccessoryCheckmark];
        editingAlbum.artist = self.pickedArtists;
        [self saveTheContext:editingAlbum.managedObjectContext];
//        NSLog(@"%d",self.pickedArtists.count);
    }
}

I think there must be some problem in managedObjectContext saving. Is it should be like this

self.managedObjectContext = [(AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
[self saveTheContext:self.managedObjectContext];

instead of

[self saveTheContext:editingAlbum.managedObjectContext];

I tried this but this is also failing to work as per expectations.

You can find my source code here

Answer 1

I have updated your code. Please check for the same. Their is a problem in relationship between Artist & Album. It must be Many to Many.

Your relationship between Album & Artist is 1 to many. Hence, if you will select Artist for multiple Album then it will override its value. Please check your database for same.

Code : Click Here