A use case describes a function that a system performs to achieve the user’s goal. A use case must yield an observable result that is of value to the user of the system.
Use cases contain detailed information about the system, the system’s users, relationships between the system and the users, and the required behavior of the system. Use cases do not describe the details of how the system is implemented.
Each use case describes a particular goal for the user and how the user interacts with the system to achieve that goal. The use case describes all possible ways that the system can achieve, or fail to achieve, the goal of the user.
You can use use cases for the following purposes:
In models that depict businesses, use cases represent the processes and activities of the business. In models that depict software systems, use cases represent the capabilities of the software.
Each use case must have a unique name that describes the action that the system performs. Use case names are often short phrases that start with a verb, such as Place Order Online.
As the following figure illustrates, a use case is displayed as an oval that contains the name of the use case.
You can add the following features to use cases:
Parent topic: Use case diagrams