/**
  * Manages all models.
  */
 public function actionIndex()
 {
     $model = new PurchaseOrder('search');
     $model->unsetAttributes();
     // clear any default values
     if (isset($_GET['PurchaseOrder'])) {
         $model->attributes = $_GET['PurchaseOrder'];
     }
     $this->render('index', array('model' => $model));
 }