Как правильно организовать связь между таблицами?

'itemMany' => array(self::MANY_MANY, 'Stock',  tbl_item_stock(item_id, stock_id)'),

$a = Stock::model()->with('Stocks')->findByPk(1);
        echo "<pre>"; print_r($a); echo "</pre>";

        foreach ($a->Stocks as $stock) {
            $cities[] = $stock->name;
        }

Stock::model()->with('Stocks')->findByPk(1);

Во-вторых, если надо найти ТОВАР=1, то и указывать надо модель ТОВАРА Item::model()...

$item = Item::model()->findByPk(1);
foreach($item->stocks as $stock) {
   $city = $stock->city;
}

$itemId = Yii::app()->request->getParam('id');

            $a = Item::model()->with('Stocks')->findByPk($itemId);

        foreach ($a->Stocks as $stock) {
            $city_id = City::model()->findByPk($stock->city_id);
            $cities[] = $city_id->name;
        }

1 таблица складов, есть id, name, city_id