Core Data (Mac) How to implement auto increment on an ID field

Question

I was wondering if anyone can point me in the direction of how to set up auto increment on an attribute in a coredata entity. I know the indexed check box just makes the field i

Answer 1

this is how apple implemented autoincrement:

 - (void) awakeFromInsert
     {
    [super awakeFromInsert];
    static int tempID = 0;
    [self setValue:[NSNumber numberWithInt:++tempID] forKey:@"id"];
}