cakephp有关问题

<?php <br />
  class BooksController extends AppController<br />
  {<br />
  	var $name='Books';<br />
  	var $help='form';<br />
function index() { <br />
$this->Book->recursive = 1; <br />
$books = $this->Book->find('all',array('field'=>array('Book.isbn','Book.title','Author.name'))); <br />
$this->set('books', $books); <br />
} <br />
function add()<br />
{<br />
   if(!empty($this->data))<br />
   {<br />
      $this->Book->create();<br />
      $this->Book->save($this->data);<br />
      $this->redirect(array('action'=>'index'));<br />
   }<br />
    $authors = $this->Book->Author->generateList();<br />
      $this->set('$authors',$authors);<br />
}<br />
} 		<br />
?>