Although Usecase derived from object-oriented development environments, he can be applied in projects using other development methods. Users don't care about what way you use to develop software. In the actual software project, we may not paint the actual example diagram, but the viewpoint of using the instance and the change of the thinking process have changed more important than whether or not the formal example of the exemplary use is more important. Usecase is a matter of viewing of the user to see questions, and the "user wants to do what the user wants the system for them". " A use instance describes the interaction order of the system and an external "executor" (A C T O R), which reflects the executor to complete a task and bring benefits to someone. The executor refers to a person, or another software application, or a hardware, or other entity interacting with the system to implement certain goals. Using an example provides a method for expressing user needs, this method must be consistent with the service needs of the system (first level of demand). Analysts and users must check each use instance, determine whether it is within the scope defined before the project is incorporated. The purpose of demand acquisition based on the "Usage Example" method is to describe all tasks that the user needs to use the system. A single usage example may include a number of logical related tasks and interactions to complete a task. So a collection of use case-related processes (S c E N A R I O)).
