Week 4 Assignment 2: Use Cases
There are a number of modeling tools and techniques that can be used to understand the design of a system. During this process, these tools and techniques can help to describe the business processes, requirements, and the users interaction with the system. One type of modeling is the functional decomposition diagram (FDD). It is similar to an organizational chart in that it uses a top-down model to describe the process. The FDD is a good way of breaking the process down from the higher-level to the lower-level processes. Another kind of modeling technique is the business process model. Business process models are good for describing business processes like filling a product order or updating a customer account. Utilizing BPM can help speed up results as well as reduce errors and lower cost. Data flow diagrams (DFD) are created out of functions in functional decomposition diagrams. A function from the FDD can be taken and described in further detail using a DFD. Yet another method of modeling is the unified modeling language (UML). The UML is a common method for visualizing and documenting software systems. It does not depend on a programming language and is good for describing business processes and requirements in a general manner. Different graphical tools are used to look at the process from the viewpoint of the end user. Sequence diagrams show a process from top to bottom while representing interaction between objects in a horizontal manner. Lastly, the use case diagram is a method that is used to show the interaction between the user and the system. The user has a specific role being performed and as they interact with the system, a use case describes each step taken and the related outcome (Shelly & Rosenblatt, 2012). The following use cases will diagram a bank customer interacting with an ATM while withdrawing, depositing, and transferring money.
Use Case 1 – ATM Withdrawal Typical Course
A bank customer arrives at the bank and pulls up to the ATM. He enters his card into the ATM and is prompted to enter his PIN number. The system asks the customer which type of transaction he would like to make. He chooses to make a withdrawal and the system displays the customer’s available accounts and asks him to choose an account to withdraw the money from. He chooses his checking account and is prompted by the system to enter in an amount for withdrawal. The customer enters in $100 and selects OK. The system asks the user if he would like a receipt with his transaction and he chooses YES. The ATM issues $100 to him in $20 bills and debits his account. A receipt is printed and the system displays a message asking the customer if he would like another transaction or his card back. He chooses to get his card back and the ATM returns it to him. The man takes his card from the ATM and drives away. Use Case 1 – ATM Withdrawal Alternate Course 1 (Incorrect PIN)
A bank customer arrives at the bank and pulls up to the ATM. He enters his card into the ATM and is prompted to enter his PIN number. He enters his PIN and the system displays a message stating the PIN is incorrect. He enters the PIN number again and the system displays the message again. The customer tries the PIN number one more time and the system displays a message on the screen that says the card has been retained after too many incorrect attempts to enter the PIN. He is asked to enter the bank to retrieve the card. The customer enters the bank to inquire about the card and is notified that the PIN he was entering is the wrong PIN for that card. He realizes he was entering the PIN number of his wife’s debit card. The card is returned to the customer and he leaves the bank.
Use Case 1 – ATM Withdrawal Alternate Course 2 (Insufficient Funds) A bank customer arrives at the bank and pulls up to the ATM. He enters his card into the ATM and is prompted to enter his PIN...
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