Requirements Analysis Using Event/Response and Use Cases – Use Cases

Planning

Now that you have a complete and comprehensive Event List, you can now use this to create your Use Cases. Before I show you how, let’s first define “Use Case”:

  • A Use Case is simply a list of steps to achieve a goal
  • It may have multiple paths (for example, the Use Case for getting cash from an ATM has the normal path, plus an alternate path for the case where a user asks for more money than in their account)
  • A Use Case Scenario is a specific path thru the Use Case

Column 4 of the Event List (“…Then We Do This”) contains the names of all of the business processes within the scope of your project. Take each of these process names and create a corresponding Use Case. Here is a collection of data elements which you can include in the Use Case:

  • Use Case Name and ID (you can use a scheme such as capital U + the Event Process ID + decimal point + the Use Case sequential number. For example, U2.1.1)
  • Use Case brief description (The process name and perhaps an additional clarifying sentence or two)
  • Sub-System Name (e.g. “Accounts Payable”)
  • Triggering Event (from the Event List)
  • “Actors” (Stakeholders that interact with or are affected by the Use Case; Your Event List is a great starting point for identifying your Stakeholders)
  • Pre-conditions: What needs to be true before the execution of this Use Case (for example, “Customer ID has been established”)
  • Post-conditions: The state of the system after execution of the Use Case (for example, “Employee has possession of a company credit card”)
  • Process Flow. Include a column for the Actors and a column for the steps executed by the Actors and the System. Do this until the process is complete and accomplishes the Post-conditions.

In the next post I will discuss deriving Functional Requirements from the Use Cases.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s