yii类别每个产品

I have two tables with the following structure:

product table :
name
category_id

product_category table:
    name
    id

I am use yii framework And I want show categories and 2 product every category. ProductCategory.php model relation :

public function relations() {
    return array(
        'products' => array(self::HAS_MANY, 'Product', 'category_id'),
    );
}

I am use this code :

$criteria = new CDbCriteria();
$criteria->with = array('products'=>array('limit'=>2));
$dataProvider = new CActiveDataProvider('productCategory', array(
    'criteria' => $criteria));

The above code show all categories and all product but I want show all categories and 2 (limit 2) product every category.

this code Just not working ('limit' is Effectless) :

$criteria->with = array('products'=>array('limit'=>2));

My main goal is to show category and 2 product every category ?