Essay about usecase diagram

Actor in a use case diagram is any entity that performs a role in one given system. This could be a person, organization or an external system and usually drawn like skeleton shown below. A use case represents a function or an action within the system.

Top level use cases should always provide a complete function required by an actor. You can extend or include use cases depending on the complexity of the system. Once you identify the actors and the top level use case you have a basic idea of the system. Now you can fine tune it and add extra layers of detail to it.

They enable you to visualize the different types of roles in a system and how those roles interact with the system. This use case diagram tutorial will cover the following topics and help you create use cases better.

The system is used to define the scope of the use case and drawn as a rectangle. This an optional element but useful when you’re visualizing large systems. For example, you can create all the use cases and then use the system object to define the scope covered by your project.