CakePHP save() doesn't save data - cakephp

Question

I don't see anything wrong with my code. But it does not save data:
<?php
class ProductsController extends AppController{
var $name = 'Products';
//var $helpers = array('Form');
//var $scaffold;
function index(){
$this->Product->recursive = 1;
$products = $this->Product->find('all');
$this->set('products',$products);
//pr($products);
}
function add(){
$categories = $this->Product->Category->find('list',array(
'field'=>array('Category.categoryName')
));
$this->set('categories',$categories);
if(!empty($this->data)){
if($this->Product->save($this->data)){
$this->Session->setFlash('Saved');
}
}
}
}
?>
it flashes "Saved" but nothing is being inserted in my table. What could possibly be wrong when it should be functioning properly. :(
Below is my add.ctp model:
<h2>ADD</h2>
<?php echo $this->Form->create('Product',array('action'=>'add')); ?>
<?php
echo $form->input('ProductName');
echo $form->input('categories');
echo $form->end('DONE');
?>

Answer 1

You have to use the create() method before to save
function add(){
$categories = $this->Product->Category->find('list',array(
'field'=>array('Category.categoryName')
));
$this->set('categories',$categories);
if(!empty($this->data)){
$this->Product->create();
if($this->Product->save($this->data)){
$this->Session->setFlash('Saved');
}
}
}