We've done a simple import that allows you to change the product code for product_ids. It differs from the standard import in that it only sets product_code and only does that if the product_id is specified. It was intended to be run as a "pre import" since the standard import will not maintain the product_id if the product code changes. Feel free to contact us.
Product code change should never be allowed. If you change product code for a SKU, order_details table data becomes completely inconsistent. This caused a huge headache with CS-Cart.
Never should be allowed to enter products without Product code
Never should be allowed to add duplicate Product code
Never should be allowed to change Product code
These are like the holy grail of having a consistent reporting in place but it is all jaked up at the moment. I got the SKU addon from Webkul, it has bugs. It works partially but causes problems when you are updating different parts of the website. It only does 1 piece of what I mentioned above. If all 3 were included in an Add-on, I would buy in heart-beat.
Never should be allowed to enter products without Product code
Never should be allowed to add duplicate Product code
Under MVE this could be acceptable, but not desireable. Especially for non-registared products (no valid UPC/GTIN).
Never should be allowed to change Product code
Don't agree with this one. There are many business reasons why someone may find it necessary to change a product code. Some reasons might be: same product now from different supplier, mistake in original, change in business practice to add/delete prefix or any other encoding that might be present in a product code.
If you change product code for a SKU, order_details table data becomes completely inconsistent. This caused a huge headache with CS-Cart.
That's why it needs to be done specifically as a single operation versus trying to do it with the general product import. It can be done quite successfully if done right.