getAllVisibleItems(), getAllItems returns items twice - magento

Question

I'm trying to do something really simple - get the items from an order. There seem to be three functions that Magento 1.7 provides for this.
getAllItems() : This returns all items twice. The items returned
are of type simple (not configurable)
getItemsCollection() : Ditto
getAllVisibleItems() : Ditto
Many of the answers that I've read elsewhere point to this problem being caused by 'parent' and 'child' products, but there are none in my DB. I've checked the tables that define the parent/child relationship and they are both empty.
Here's the code that I'm running :
$order = Mage::getModel("sales/order")->load($order_id, 'increment_id'); //load order by order id
$ordered_items = $order->getAllVisibleItems();
//$ordered_items = $order->getAllItems();
//$ordered_items = $order->getItemsCollection();
foreach($ordered_items as $item)
{
if($this->debug)
{
echo $item->getItemId()."</br>";
echo $item->getProductId()."</br>";
echo $item->getSku()."</br>";
echo $item->getQtyOrdered()."</br>";
echo $item->getName()."</br>";
}
echo("*************************************************</br>");
}
And the output is
6
934
1003
1.0000
ProductA
*************************************************
6
934
1003
1.0000
ProductA
*************************************************
As you can see the first figure outputted is the actual entity_id - so I'm getting real duplication of the same item?

Answer 1

You have to use this code
$order = Mage::getModel("sales/order")->load($order_id, 'increment_id');
$_items = $order->getItemsCollection();
foreach ($_items as $item) {
if ($item->getParentItem()) continue;
//do something
echo $item->getSku();
}