Unified Modeling Language (UML) Question:

Use case diagram is a subset of various behaviour diagrams. Use case diagrams are used to provide concrete examples of the elements which are supposed to implement. It is used to analyze objects.

The following are the elements of the use case diagrams:

Actors: An actor is one of the entities who perform certain actions. These roles are the actual business roles of the users in given system. An actor interacts with a use case of the system. For example, for a banking system, a customer is one of the actors.

Use Case: A use case is a use case diagram of UML represents a business functionality that is distinct. The use case should list the discrete business functionality that is specified in the problem statement. Every business functionality is a potential use case.

System boundary: A system boundary defines the scope of the system. The systems that use cases also need to be defined in the limits of the system. The system boundary is shown as a rectangle that spans all use cases of the system.