Use Cases

As we saw in the previous blog where we talked about Unified Software Process, Use Cases are a fundamental approach used in software development. But what exactly are the “Use Cases”? Is this approach really useful? In this post, we´ll find out.

We will start defining a Use Case as a analysis system that helps identify, clarify and organize the requirements of a system for the user. This list of requirements specified by the costumer are converted to functional requirements which are referred to as the “use-cases”.

Similarly, a use case can be the list of actions or event steps, typically defining the interactions between a role, such as an actor and a system, for it to achieve a goal.

Why is it important?

Use cases let us describe the goals that at the same time provides a general summary of what the system will offer. This is, giving an overview of the roles of each and every component in the system, helping us define the roles of users, administrators, etc. and exploring the maximum operation of the project itself.

Drawing a Use Case…

A Use case model can be develop by following these general steps:

1. Identify the Actors of the system.
2. For each category of users, identify, all roles played by the users relevant to the system.
3. Identify what are the users required the system to be performed to achieve these goals.
4. Create use cases for every goal.
5. Structure the use case.
6. Prioritize, review, estimate and validate the users.

Use Case Diagram Notations.

Actor: individuals involved with the system defined according to their roles. The actor can be a human or other external system.

Use Case: describes how actors uses a system to accomplish a particular goal. Use cases are typically initiated by a user to fulfill goals describing the activities and variants involved in attaining the goal.

Relationship: The relationships between and among the actors and the use cases.

System Boundary: The system boundary defines the system of interest in relation to the world around it.

Show me the way, how to create a Use Case?

Showing up next, I will share with you a more in-depth video from Lucidchart of how to create a Use Case with UML. Let us remember that UML it is the best known and used software systems modeling language today.

Summary.

A use case describes how a user uses a system to accomplish a particular goal. Think it about this way, a use case diagram consists of the system, the related use cases and actors and relates these to each other to visualize: what is being described? (in terms of the system), who is using the system? (in terms of the actors) for what do the actors want to achieve? Use cases help ensure that the correct system is developed by capturing the requirements from the user’s point of view.