title: Updating timestamps with #update_all
body: <p>When I have list of ids that I want to update their property the <code>updated_at</code> field in the database doesn't seem to change, here is what I mean :</p>
  
  <pre><code>ids = [2,4,51,124,33]
  MyObj.where(:id =&gt; ids).update_all(:closed =&gt; true)
  </code></pre>
  
  <p>After this update is executed <code>updated_at</code> field doesn't change. However when I enter rails console with <code>rails c</code> and do this :</p>
  
  <pre><code>obj = MyObj.find(2)
  obj.closed = false;
  obj.save!
  </code></pre>
  
  <p>After this statement <code>updated_at</code> field changes value. Why is this? I'm relying on this <code>updated_at</code> field in my app as I'm listening to the updates and doing whole app flow when this happens?</p>
  
  <p><strong>Edit</strong></p>
  
  <p>I just found out from <code>dax</code> answer that : </p>
  
  <pre><code>Timestamps
  
  Note that ActiveRecord will not update the timestamp fields (updated_at/updated_on) when using update_all().
  </code></pre>
  
  <p>I don't want to be updating one record at a time, is there a way around this? without resorting to sql level?</p>