Let's look at the sequence of actions performed by typical users who visit the web site for shopping. New users coming to the site for the first time register themselves. Existing users authenticate themselves by providing their user id and password. After authentication is successful, the user, having browsed the music/book titles, adds the items to their cart. Additionally, they can view the list of items in their cart. The user might want to change the quantities of the items or delete the items selected earlier.
After the user is sure that they want to buy all the items in their cart, they check out. Checking out is the confirmation from the user that they want to buy all the items in the cart. After the user has checked out, all the items in the user's cart are entered in the database, and these items are shipped to the address of the user, given at the time of registration. After checking out, the user can continue shopping or can decide to log out.
Users can also just browse the music and book titles available in the shopping site, without purchasing any items.
Sometimes users are interested in viewing the current status of their account, and the status of items (for example whether they have been shipped or not) purchased by them earlier.
The flow chart below describes the interaction of the user with the shopping cart application:
