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 remai
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();