objective c - iphone Core Data Unresolved error while saving

Question

I am getting a strange error message from the core data when trying to save but the problem that the error is not reproducible ( it appears at different times when doing different tasks)

the error message:

Unresolved error Domain=NSCocoaErrorDomain Code=1560 UserInfo=0x14f5480 "Operation could not be completed. (Cocoa error 1560.)", {
NSDetailedErrors = (
Error Domain=NSCocoaErrorDomain Code=1570 UserInfo=0x5406d70 "Operation could not be completed. (Cocoa error 1570.)",
Error Domain=NSCocoaErrorDomain Code=1570 UserInfo=0x14f9be0 "Operation could not be completed. (Cocoa error 1570.)"
);
}

and the method that generates the error is:

- (IBAction)saveAction:(id)sender {
    NSError *error;
    if (![[self managedObjectContext] save:&error]) {
        // Handle error
        NSLog(@"Unresolved error %@, %@, %@", error, [error userInfo],[error localizedDescription]);
        exit(-1);  // Fail
    }
}

any idea for the reason of this message ? giving that it appears at random times

Answer 1

It means there's a mandatory property has been assigned nil. Either in your *.xcodatamodel check the "optional" box or when you are saving to the managedObjectContext make sure that your properties are filled in.

If you're getting further errors after changing your code to suit the two requirements try cleaning your build and delete the application from your iPhone Simulator/iPhone device. Your model change may conflict with the old model implementation.

Edit:

I almost forgot here's all the error codes that Core Data spits out: Core Data Constants Reference I had trouble with this before and I realised I unchecked the correct optional box. Such trouble finding out the problem. Good luck.