A web based software for an online book store is to be developed when a valid customer logon to the site a list of available books is displayed. When the customer selects the required book a form will be displayed that will take input the credit card number and other necessary information of the user.

After submission of the form by the customer the validity of the credit card is ensured by a banking system (external to the system). The valid orders are passed to the shipment department and an email is sent to the customer that his order is being shipped.