title: CodeIgniter/PHP Active Record won't increment an integer
body: <p>Here's my query, in CodeIgniter's Active Record:</p>
  
  <pre><code>function calculate_invites($userid)
  {
      $this-&gt;db-&gt;where('id', $userid)
                 -&gt;update('users', array('invites' =&gt; 'invites-1', 'sentinvites' =&gt; 'sentinvites+1'), FALSE);
  }
  </code></pre>
  
  <p>The fields <code>invites</code> and <code>sentinvites</code> are both integers but are set to 0 after the function is run. This makes me presume that CodeIgniter is passing <code>invites-1</code> and <code>sentinvites+1</code>  as strings, but I thought appending <code>FALSE</code> to the end stopped it doing that?</p>
  
  <p>Thanks!</p>
  
  <p>Jack</p>