What is a UML Use Case Diagram?
Use case diagrams model the functionality of a system using actors and use cases. Use cases are services or
functions provided by the system to its users.
Basic Use Case Diagram Symbols and Notations
Draw your system's boundaries using a rectangle that contains use cases. Place actors outside the system's
Draw use cases using ovals. Label with ovals with verbs that represent the system's functions.
Actors are the users of a system. When one system is the actor of another system, label the actor system with the
Illustrate relationships between an actor and a use case with a simple line. For relationships among use cases, use arrows
labeled either "uses" or "extends." A "uses" relationship indicates that one use case is needed by another in order
to perform a task. An "extends" relationship indicates alternative options under a certain use case.
Learn how to draw relationships.