You are the audit senior assigned to the audit of Speedy Ltd, a motor vehicle spares company.  

You obtain an understanding of the ordering function within the acquisition and payments cycle at Speedy Ltd. 

The order clerk prepares the purchase requisition by accessing the purchase order module on the system with his username and password. The system is set up so that once the order clerk keys in the inventory item code, the screen will automatically reflect the description of the goods and identify from the approved supplier list which supplier the item should be ordered from, along with the supplier inventory code. If the inventory item code is incorrect, the order clerk will be unable to proceed with the purchase requisition. 

Which one of the following programme controls has been implemented above, ensuring that the correct goods are being purchased?