OOP Zend Framework vraag

<?php

class GuestbookController extends Zend_Controller_Action
{
    private $guestbook;
    private $form;
    

    public function init()
    {
        $this->guestbook = new Application_Model_DbTable_Guestbook_Db();
        $this->form = new Application_Form_Guestbook_Form();
    }

    public function indexAction()
    {
        $this->view->guestbook = $this->guestbook->fetchAll();
    }
    
    public function addAction()
    {
        $this->form->submit->setLabel('Add Message');
        $this->view->form = $this->form;
        if ($this->getRequest()->isPost()) {
            $formData = $this->getRequest()->getPost();
            if ($this->form->isValid($formData)) {              
                $username = $this->form->getValue('username');
                $email    = $this->form->getValue('email');
                $message  = $this->form->getValue('message');
                $date     = date("y-m-d H:m:s");
                $this->guestbook->addMessage($username, $email, $message, $date);
                $this->_helper->redirector('index');
            } else {
                $this->form->populate($formData);
            }
        }   
    }
    public function deleteAction()
    {
        if ($this->getRequest()->isPost()) {
            $del = $this->getRequest()->getPost('del');
            if ($del == 'Yes') {
                $id = $this->getRequest()->getPost('id');
                $this->guestbook->deleteMessage($id);
            }
            $this->_helper->redirector('index');
        } else {
            $id = $this->_getParam('id', 0);
            $this->view->guestbook = $this->guestbook->getMessage($id);
        }
    }
    
    
    public function editAction()
    {
        $this->form->submit->setLabel('Save');
        $this->view->form = $this->form;
        if ($this->getRequest()->isPost()) {
            $formData = $this->getRequest()->getPost();
            if ($this->form->isValid($formData)) {
                $id       = (int)$this->form->getValue('id');
                $username = $this->form->getValue('username');
                $message  = $this->form->getValue('message');
                $this->guestbook->updateMessage($id, $message);
                $this->_helper->redirector('index');
            } else {
                $this->form->populate($formData);
            }
        } else {
            $id = $this->_getParam('id', 0);
            if ($id > 0) {
                $this->form->populate($this->guestbook->getMessage($id));
            }
        }
    }    
}

?>

<?php

class Application_Model_DbTable_Guestbook_Db extends Zend_Db_Table_Abstract
{

    protected $_name = 'guestbook';

    public function init()
    {
        $row = $this->fetchAll();
        if (!$row) {
            throw new Exception("Could not find any guestbook messages");
        }
        return $row->toArray();
    }
    
    public function addMessage($username, $message, $date)
    {
        $data = array(
            'username' => $username,
            'message' => $message,
            'date' => $date,
        );
        $this->insert($data);
    }
    
    public function deleteMessage($id)
    {
        $this->delete('id =' . (int)$id);
    }
    
    public function getMessage($id)
    {
        $id = (int)$id;
        $row = $this->fetchRow('id = ' . $id);
        if (!$row) {
            throw new Exception("Could not find row $id");
        }
        return $row->toArray();
    }
    public function updateMessage($id, $message)
    {
        $data = array('message' => $message);
        $this->update($data, 'id = '. (int)$id);
    }
}
?>

<?php

class Application_Form_Guestbook_Form extends Zend_Form
{

    public function init()
    {
        $this->setName('guestbook');

        $username = new Zend_Form_Element_Text('username');
        $username->setLabel('Username')
            ->setRequired(true)
            ->addFilter('StripTags')
            ->addFilter('StringTrim')
            ->addValidator('regex', false, array('/^[a-zA-Z]+/'))
            ->addValidator('stringLength', false, array(6, 20))
            ->addValidator('NotEmpty');       
        
        
        $email = new Zend_Form_Element_Text('email');
        $email->setLabel('Email')
            ->setRequired(true)
            ->addFilter('StripTags')
            ->addFilter('StringTrim')
            ->addValidator('EmailAddress')
            ->addValidator('NotEmpty');
        
        $captcha = new Zend_Form_Element_Captcha('image', 
            array(
                'label' => "Captcha",
                'captcha' => 'Image',
                'captchaOptions' => 
            array(
                'captcha' => 'Image',
                'wordLen' => 4,
                'timeout' => 300,
                'imgDir' => '../public/images/captcha',
                'width' => 155,
                'height' => 45,
                'font' => 'fonts/verdana.ttf'
            ),
        ));
        
        $message = new Zend_Form_Element_Textarea('message');
        $message->setLabel('Message')
            ->setRequired(true)
            ->addFilter('StripTags')
            ->addFilter('StringTrim')
            ->addValidator('regex', false, array('/^[a-zA-Z]+/'))
            ->addValidator('stringLength', false, array(6, 500))
            ->addValidator('NotEmpty');
        
        
        $submit = new Zend_Form_Element_Submit('submit');
        $submit->setAttrib('id', 'submitbutton');
        
        $this->addElements(array($username, $email, $captcha, $message, $submit));
    }
}
?>

<?php         
$this->title = "My Guestbook";
$this->headTitle($this->title);
$auth = Zend_Auth::getInstance();
?>
<p><a href="<?php echo $this->url(array('controller'=>'guestbook', 
        'action'=>'add'));?>">Add new message</a></p>
<table>
<tr>
    <th class="username">Post By</th>
    <th class="message">Message</th>
    <?php
    if ($auth->hasIdentity() && $auth->getIdentity('id') == "admin") {?>
        <th class="options">Option</th>
    <?}?>
</tr>
<?php foreach($this->guestbook as $guestbook) : ?>
<tr>
    <td class="username"><?php echo $this->escape($guestbook->username);?></td>
    <td class="message"><?php echo Application_Model_Parser_Html::Pars($guestbook->message);?></td>
    <?php
    if ($auth->hasIdentity() && $auth->getIdentity('id') == "admin") {?>
    <td class="options">
        <a href="<?php echo $this->url(array('controller'=>'guestbook', 
            'action'=>'edit', 'id'=>$guestbook->id));?>">Edit</a>
        <a href="<?php echo $this->url(array('controller'=>'guestbook', 
            'action'=>'delete', 'id'=>$guestbook->id));?>">Delete</a>
    </td>
    <?}?>
</tr>
<?php endforeach; ?>
</table>