What is Usecase diagram and its importance : Business Analysts and System Analysts FAQ

People in the Information Technology industry and other allied industries might have heard the term “Use Case “. They might be aware of its importance and how helpful they may be in executing projects, but if you are a newbie in this industry or just have to refresh your knowledge then it might be a good idea to just read up again on Use Cases and their importance.

So what is a USE CASE?

The technical definition of a USE CASE is that it is a description of a system’s behavior or a particular scenario in which a system responds to an external request that originates. An example of an external request is a user input.

Basically, a use case is helpful to understand the system from the end-user who is ultimately to actually use the system’s point of view. Use cases help to specify and explain the interaction between the actors and the system. Now the question that may arise in your head is who is an actor?

An actor is the one who initiates an action with the system and the Use Case is what is used as a tool to describe the sequences of the course of the action. These sequences of actions between actors and system are called scenarios or use case instances. Hence the Use case comprises actors and scenarios which describe the interactions of the system.

This is the simplest way to understand what Use cases are in software engineering and what they do. Actors could be anybody from persons who are the users of the system to organizations and computer systems too. They are basically initiators of the system.

Use cases are thus an organized way of categorizing the various system requirements. All system interactions or activities that are important and should be categorized since they are of value to the users of the designed system can be identified by using Use cases.

Thus the Use case is nothing but a systematic sequence of requirements, actions and interactions between system and users and vice versa and has some value. Use cases are easy to read and understand and hence they are widely used. However, it is worthy to remember that use cases do not specify details of the actions, only their intent and Use cases do not give implementation details. They are multi level.

Importance of Use cases:

Use cases are important because they are in a tracking format. Hence they make it easy to comprehend about the functional requirements in the system and also make it easy to identify the various interactions between the users and the systems within an environment. They are descriptive and hence clearly represent the value of an interaction between actors and the system. They clarify system requirements very categorically and systemically making it easier to understand the system and its interactions with the users. During the analysis phase of the project’s System Development Life Cycle, use cases help to understand the system’s functionality.