import_products_update.php

<?php

ini_set('memory_limit','256M');
ini_set("max_execution_time", "0");	
set_time_limit(0); 
	
 define('MAGENTO', realpath(dirname(__FILE__)));
 require_once MAGENTO . '/app/Mage.php';
 
 umask(0);
 
 Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);
 $count = 0;
 
 $file = fopen(MAGENTO . '/catalog_product_SIMPLE_QTY_20120923.csv', 'r');
	while (($line = fgetcsv($file)) !== FALSE) { 
	 if ($count == 0) {
		foreach ($line as $key=>$value) {
			$cols[$value] = $key;
		}
	 }	 
	 $count++;
	 
	 if ($count == 1) continue;
	 
	 #Convert the lines to cols
	if ($count > 0) {
	 foreach($cols as $col=>$value) {
		unset(${$col});
		${$col} = $line[$value];
		}
	 }
	 
	 // Check if SKU exists
	 $product = Mage::getModel('catalog/product')->loadByAttribute('sku',$sku);
	 
	 if ( $product ) {
	 
		 $productId   = $product->getIdBySku($sku);
		 $stockItem   = Mage::getModel('cataloginventory/stock_item')->loadByProduct($productId);
		 $stockItemId = $stockItem->getId();
		 $stock 	  = array();
		 
		 if (!$stockItemId) {
			$stockItem->setData('product_id', $product->getId());
			$stockItem->setData('stock_id', 1);
		 } else {
			$stock = $stockItem->getData();
		 }
		 
		 foreach($cols as $col=>$value) {
			$stock[$col] = $line[$value];
		 }
		 
		 foreach($stock as $field => $value) {
			$stockItem->setData($field, $value?$value:0);
		 }
		 
		 
		 $stockItem->save();
		 
		 unset($stockItem);
		 unset($product);
	 }	 
	 echo "<br />Stock updated $sku - $qty";
 
 }
 fclose($file);
 
?>