title: Disable timestamp update in codeigniter
body: <p>Faced the problem: when i am trying to update field via <code>active record</code> in <code>CodeIgniter</code> there also updates <code>timestamp</code> field. For example my code:</p>
  
  <pre><code>$this-&gt;db-&gt;where('user_i', 1);
  $this-&gt;db-&gt;update('ci_users', $user_info);
  </code></pre>
  
  <p>Creates this sql:</p>
  
  <pre><code>UPDATE `ci_users` SET `user_fullname` = 'asdasdfsafd' WHERE `user_iD` =  1
  </code></pre>
  
  <p>But after execution there also changes <code>ci_users.user_creation_date</code> field. Where there may be a problem? </p>