title: how to delete an entity in a one to one relation?
body: <p>I have two tables in my database in a one to one realtionship, is a weak relationship.</p>
  
  <p>Videos(IDVideo, IDType, year, ...)
  Serie(IDSerie, IDVideo, ...)</p>
  
  <p>When I try to change the type of the video, if the new type is not a serie, I would like to delete the row in the series table that belongs to this video. So I follow this steps:</p>
  
  <pre><code>Videos myVideoDB = myContext.Videos.Include("Series").Where(v=&gt;v.IDVideo == paramVideo.IDVideo).FirstOrDefault&lt;Videos&gt;();
  
  myContext.Series.Remove(myVideoDB.Series.ElementAt(0));
  </code></pre>
  
  <p>in this second line I get the following error:</p>
  
  <pre><code>Multiplicity constraint violated. The role 'videos' of the relationship 'xxx' has the multiplicity 1 or 0..1.
  </code></pre>
  
  <p>Why? I think that when I delete the Serie, the DbContext knows  that it must delete the entity from the collection of Videos. Otherwise, I try to delete first the entity from the collection of videos and then delete the serie but the problem is not solved.</p>
  
  <p>Thanks.</p>