title: Core Data - Order of objects in a to-many relationship
body: <p>My app is a music library app, the user has their songs, and they can create playlists.<br>
  I want the order of the songs in the playlist to be in the order that the user adds those songs to that playlist.</p>
  
  <p>My core data objects:</p>
  
  <pre><code>Song
  =====
  name
  duration
  album
  
  artist (to one relationship)
  
  Playlist
  ========
  title
  
  songs (to many relationship)  
  </code></pre>
  
  <p>I have a tableview of playlists, each row in that table shows the title of the playlist and the name of the last song added to that playlist.  </p>
  
  <p><strong>I have two questions:</strong></p>
  
  <ol>
  <li>How can i know what was the last song the user added to the playlist? even more how can I know the order of the songs in a given playlist? </li>
  <li>How should I fetch that last song name when i'm building the playlists tableview?</li>
  </ol>