繼承至 NSManagedobject 的 Entity 當作一般物件使用

NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Device" inManagedObjectContext:[[WPCoreDataCenter sharedMainCenter] mainManagedObjectContext]];
Device *device = [[Device alloc] initWithEntity:entityDescription insertIntoManagedObjectContext:nil];
device.idnum = @"A845dd7412b56";
device.serial = @"SMACODZL";