title: For a database collection, should FirstOrDefault return null?
body: <p>I am puzzled by the expected behaviour or the family of LINQ methods <code>SingleOrDefault</code>, <code>FirstOrDefault</code>, <code>LastOrDefault</code> and <code>ElementAtOrDefault</code> methods, operating on a database.</p>
  
  <p>Should they return:</p>
  
  <ol>
  <li>null, or</li>
  <li>a new object populated with default values?</li>
  </ol>