title: Passing objects beteen ViewControllers and CoreData updates
body: <p>I have a UITableView in an iOS project. When the user selects an item from the table, the object is retrieved from CoreData and stored in a "Player" object. This player object is then passed into another view controller.</p>
  
  <p>My question is: If i make changes to attributes in this Player object, how do i then save those changes. How does CoreData know which Player object changed? I have not set up a playerID attribute as all the Core Data documentation says that it manages its own IDs and references.</p>
  
  <p><strong>MORE:</strong></p>
  
  <p>So, at the moment, im doing this (excuse the pseudo-code, i dont have my source code to hand right now):</p>
  
  <p><code>Player *player1 = [NSFetchResultController objectAtIndex:0]<br>
  Player *player2 = [NSFetchResultController objectAtIndex:1]<br>
  GameViewController *gameVC = [[GameViewController alloc] init]<br>
  gameVC.player1 = player1;<br>
  gameVC.player2 = player2;<br>
  gameVC.managedObjectContext = self.managedObjectContext<br>
  [self performSegueWithIdentifier:@"Game"]</code> </p>
  
  <p>I am passing in objects of type Player to gameVC, which have no identifier (as Core Data doesnt need explicit ID attributes creating - allegedly!)</p>
  
  <p>So how does the MOC in gameVC know exactly which objects to commit any changes to???</p>