Cannot update Stock Item Quantity for a Product in Magento 1.6.2

Question

I am trying to update the stock quantities of products in Magento from within a script.

I load the product, set the stock quantity, and save - but the quantity remains unchanged.

// get stock data
$stockData = $product->getStockItem();
printf(PHP_EOL.'Stock: qty=%d, instock=%s, man_stock=%s, use_cfg_man_stock=%s'.PHP_EOL,
    $stockData->getData('qty'),
    $stockData->getData('is_in_stock'),
    $stockData->getData('manage_stock'),
    $stockData->getData('use_config_manage_stock')
);
// prints out qty=0, instock=, man_stock=, use_cfg_man_stock=


// $stockQty = 1
$product->stockItem->setData('qty', $stockQty);
$product->stockItem->setData('is_in_stock', $stockQty>0 ? 1 : 0);
$product->stockItem->setData('manage_stock', 1);
$product->stockItem->setData('use_config_manage_stock', 0);

$product->save();                           
$product->load();                           
$stockData = $product->getStockItem();
printf('New Stock: qty=%d, instock=%s, man_stock=%s, use_cfg_man_stock=%s'.PHP_EOL,
    $stockData->getData('qty'),
    $stockData->getData('is_in_stock'),
    $stockData->getData('manage_stock'),
    $stockData->getData('use_config_manage_stock')
);
// prints out qty=0, instock=, man_stock=, use_cfg_man_stock=

Where am I going wrong?

Answer 1

All you were missing is to save the $stockItem. You shouldn't need to create a new stock_item nor should you have to save the product.

if (!($stockItem = $product->getStockItem())) {
    $stockItem = Mage::getModel('cataloginventory/stock_item');
    $stockItem->assignProduct($product)
              ->setData('stock_id', 1)
              ->setData('store_id', 1);
}
$stockItem->setData('qty', $stockQty)
          ->setData('is_in_stock', $stockQty > 0 ? 1 : 0)
          ->setData('manage_stock', 1)
          ->setData('use_config_manage_stock', 0)
          ->save();