title: filtering only n elements in django model
body: <p>Well this is a simple question i want to filter two elements sorted reverse by date. </p>
  
  <p>The model is:</p>
  
  <pre><code>Class ModelName(models.Model):
      usr = models.ForeignKey(UserProfile)
      created = models.DateTimeField(default=datetime.datetime.now)
  </code></pre>
  
  <p>The way i do it is:</p>
  
  <pre><code>ModelName.object.filter(param=param).order_by('-created')[:2]
  </code></pre>
  
  <p>As per my understanding what i think happens behind the scene is:</p>
  
  <ol>
  <li><p>All the objects from ModelName are filtered </p></li>
  <li><p>they are sorted </p></li>
  <li><p>only two of them are selected. </p></li>
  </ol>
  
  <p>Maybe i am wrong, if not then how can i filter only last two elements based on the date. </p>