title: Core data, managed objects and multiple table view controllers
body: <p>I have a <code>UITabBarController</code> with two tabs.  Each tab has a <code>UINavigationController</code> and each <code>UINavigationController</code> has a table view.  The first tab lets you see and edit a list of all employees.  The second tab lets you see a subset of the employees.</p>
  
  <p>My problem is that in the first tab you can delete an employee from core data.  However, when you go back to the second tab it crashes because it still has a pointer to the deleted employee.</p>
  
  <p>Is there an easy way to check if an <code>nsmanaged</code> object has been deleted, or is there a way to notify or listen for deletions?</p>