title: Issues with Entity Framework Datetime Field and default values
body: <p>Its properly because I do not understand completely, but I have had these issues a few days now. </p>
  
  <p>I have a datetime field and using entity framework.</p>
  
  <p>Scenarios:</p>
  
  <ol>
  <li><p>When I set the field to be computed (databasegenerated option) I cant update the field like this:</p>
  
  <pre><code>    db.ComputeUnites.Find(this._ComputeGuid).HeartBeat = DateTime.UtcNow;
      db.SaveChanges();
  </code></pre></li>
  <li><p>When I don't set it to computed, and set it to required. I get an error when I try to add a new element that do not have the field set. (this makes sense, but I have set the default value on the server to set it to (<code>getutcdate()</code>)- so I hoped it would kick in when not set.</p></li>
  <li><p>I tried to set it to optional and with a default value again, then I can add new objects, but the default value is not used, instead 0:0:0 00:000 (don't remember the syntax correctly) times are inserted.</p></li>
  </ol>
  
  <p>What I would like is: When I do not set the field on a newly added object, the default value should be used. And if I provide or update the field, it should use the value coming from my c# class. </p>
  
  <p>What am I missing?</p>