• A catalog display
• Shopping cart capabilities
• Transaction processing

Larger more complex sites adds other features to the basic set of commerce tools. These include:

• Middleware that integrates the electronic commerce system with existing company information systems that handle inventory control, order processing, and accounting
• Enterprise application integration
• Web services
• Integration with enterprise resources planning (ERP) software
• Supply chain management (SCM) software
• Customer relationship management (CRM) software
• Content management software
• Knowledge management software

  A. Catalog Display: A catalog organizes the goods and services being sold. A small commerce site can have a very simple static catalog. A catalog is a listing of goods and services. A static catalog is a simple list written in HTML that appears on a Web page or a series of Web pages. To add an item, delete an item, or change an item’s listing, the company must edit the HTML of one or more pages. Larger commerce sites are more likely to use a dynamic catalog. A dynamic catalog stores the information about items in a database, usually on a separate computer that is accessible to the server that is running the Web site itself. A dynamic catalog can feature multiple photos of each item, detailed descriptions, and a search feature that allows customers to search for an item and determine its availability.

  B. Shopping Cart: In the early days of electronic commerce, shoppers selected items they wanted t o purchase by filling out online forms. Using text box and list box form controls to indicate their choices, users entered the quantity of an item in the quantity text box, the SKU (stock-keeping unit) or product number in another text box, and the unit price in yet another text box. This system was awkward for ordering more than one or two items at a time.

  The forms-based method of ordering has given way to electronic shopping carts. Today, shopping carts are a standard of electronic commerce. A shopping cart, sometimes called a shopping bag or shopping basket, keeps track of the items the customer has selected and allows customers to view the contents of their carts, add new items, or remove items. To order an item, the customer simply clicks that item. All of the details about the item, including its price, product number, and other identifying information, are stored automatically in the cart. If a customer later changes his or her mind about an item, he or she can view the cart’s contents and remove the unwanted items. When the customer is ready to conclude the shopping session, the click of a button executes the purchase transaction.
  
  C. Transaction Processing: Transaction processing occurs when the shopper proceeds to the virtual checkout counter by clicking a checkout button. Then the electronic commerce software performs any necessary calculations, such as volume discounts, sales tax, and shipping costs. At checkout, the customer’s Web browser software and the seller’s Web server software both switch into a secure state of communication.

  Transaction processing can be the most complex part of the online sale. Computing taxes and shipping costs are important parts of this process, and site administrators must continually check tax rates and shipping tables to make sure they are current. Some software enables the Web server to obtain updated shipping rates by connecting directly to shipping companies to retrieve information.