title: Changing specific symbol of YII cactiverecord model's attribute
body: <p>How to change specific symbol of YII cactiverecord model's attribute ?
  Dont understand why it doesnt work:</p>
  
  <pre><code>echo $model-&gt;attr; // aaa
  $model-&gt;attr[1] = 'b';
  echo $model-&gt;attr; // aaa
  </code></pre>