Store But Don't Save NSManagedObject to CoreData?

You can also use

NSEntityDescription *ed = [NSEntityDescription entityForName:@"YourManagedObject" inManagedObjectContext:managedObjectContext];
YourManagedObject *obj = [[[YourManagedObject alloc] initWithEntity:ed insertIntoManagedObjectContext:nil] autorelease];

to create the managed object without inserting it into your context. You can do that later by calling [managedObjectContext insertObject:obj];.

When you are dealing with CoreData, all add/modify/delete actions occur in the NSManagedObjectContext - but changes are not persisted to disk until you call 'save' on that context.

So the answer is yes - this is the behavior you should already be getting. If you are adding or modifying the properties of NSManagedObjects, these changes are kept in the memory of the context, but are not being saved to disk until you actually call 'save'.