title: Ruby On Rails self saving in model
body: <p>I have a function in my model that changes is as follows:</p>
  
  <pre><code>  def compare
          self.dirty = 1 if self.dirty == 0
          compare_recursive(0, MergeDigestTree.all)
          self.dirty = 0;
    end
  </code></pre>
  
  <p>Do I have to call self.save or is it fine like this</p>