Use Case Definition
A use case is a list of actions or event steps, typically defining the interactions between a role (known in the Unified Modeling Language as an “actor”) and a system, to achieve a goal. The actor can be a human or other external system. In systems engineering, use cases are used at a higher level than within software engineering, often representing missions or stakeholder goals.
Use Case Key Points
- A use case represents a distinct functionality of a system, a component, or a piece of software.
- It describes the method through which an actor interacts with the system to achieve a specific goal.
- Use cases are often used in software development to identify and clarify system requirements, and to create test cases.
- They are typically documented in diagrams or as structured text.
What is a Use Case?
A use case is a description of a system’s behavior as it responds to a request that originates from outside of that system. In other words, a use case describes “who” can do “what” with the system in question. The “who” are often humans or other systems, referred to as the “actors” of the use case. The “what” is a goal that the system fulfills for the actor.
Why are Use Cases Important?
Use cases are important because they clearly define the interaction between the system and the actors, allowing developers to understand the goal of each function. They provide a clear and concise way to communicate how a system should behave and how it will be used in the real world. They also help to identify any potential issues or problems with the system early in the development process.
Who Uses Use Cases?
Use cases are used by a variety of individuals in the software development process. These can include:
- Business Analysts: They use use cases to understand and document business requirements.
- System Architects: They use use cases to understand and design the system architecture.
- Software Developers: They use use cases to understand the system requirements and to design, implement, and test the system.
- Testers: They use use cases to create test cases and test scripts.
When are Use Cases Used?
Use cases are used throughout the software development lifecycle. They are typically created during the requirements gathering phase and are then used during the design, implementation, and testing phases to ensure that the system meets the intended goals.
How are Use Cases Created?
Creating a use case involves the following steps:
- Identify the actors: These are the entities that will interact with the system. They can be users, other systems, or hardware devices.
- Identify the goals: These are the objectives that the actors want to achieve by interacting with the system.
- Define the interactions: These are the steps that the actors take to achieve their goals, and how the system responds to those actions.
- Document the use case: This can be done in a variety of formats, including use case diagrams, structured text, or storyboards.
