title: Core-data one to many relationship loses his relationship after fetching new objects
body: <p>I've asked this question <a href="https://stackoverflow.com/questions/19374504/core-data-relationship-lost-after-fetching-more-objects-into-the-entities">before</a>. But i'm opening a new one because I have some other insights now. First of all this is how my <code>core data model</code> looks like.</p>
  
  <p><img src="https://i.stack.imgur.com/n7TGc.png" alt="enter image description here"></p>
  
  <p>Now when I fetch my first <code>appointments</code> into my model. Everything works oké. But the problem comes when I load up new appointments. Then the previous appointments location relation goes to <code>NULL</code>. The strange things is that the <code>location relationship</code> only works with the appointments that are last loaded in.</p>
  
  <p><img src="https://i.stack.imgur.com/NrpNe.png" alt="enter image description here"></p>
  
  <p>I'm using <code>restkit</code> for mapping my <code>JSON</code> into my <code>core-data model</code>. And this is how I made the relationship.</p>
  
  <pre><code> [locationMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"appointments" toKeyPath:@"appointments" withMapping:appointmentMapping]];
  </code></pre>
  
  <p>Can anybody help me with this  problem ?</p>