Magento bundle products - selection_id cannot be null? - sql

Question

I am trying to create a bundled product programmatically, and setting the options via this:
$new_options[$count] = array(
'required' => 0,
'position' => 1,
'parent_id' => $parentProduct->getId(),
'type' => 'select',
'title' => $product->getName(),
'default_title' => $product->getName()
);
$new_selections[$count] = array(array(
'product_id' => $product->getEntityId(),
'selection_qty' => $child['qty'],
'selection_can_change_qty' => 0,
'position' => 0,
'is_default' => 1,
'selection_price_type' => 0,
'selection_price_value' => 0.0
));
...
$parentProduct->setBundleOptionsData($new_options);
$parentProduct->setBundleSelectionsData($new_selections);
Which looks correct (as described in https://stackoverflow.com/a/4415800/494643). However, it is not working - I get an SQL exception complaining that Column 'selection_id' cannot be null'. How do I get around this? The selection id is an auto_increment column, so I can't get it until it is created, but it looks like it cannot be created?

Answer 1

The solution lies in the _beforeSave function of the Mage_Bundle_Model_Selection model.
This causes it to attempt to write the selection_id to the catalog_product_bundle_selection_price table, before it has saved the selection object - and therefore before it has generated a selection_id. The answer therefore is to force it to generate an id before it saves, so looking again at the _beforeSave function, we can see that it only saves the price if the store is not 0.
Specifically, this part:
$storeId = Mage::registry('product')->getStoreId();
if (!Mage::helper('catalog')->isPriceGlobal() && $storeId) {
which means that if we set the store id of the registry product to 0 first, we can cause it to save the selection, without saving the price. We would then need to reset the store to the previous value, and save again, to record the price - although only after having reloaded the object to get the newly generated selection id.