1. Actors and use cases are determined by the analysis of functional requirements, and a use case diagram is a visual representation of actors and use cases.
2. Actor
1. An actor is the role played by someone or something outside the topic for a use case. A participant does not necessarily represent a person, but can be an organization or a machine.
2. Wooden man representation.
3. Use Case
1. A use case represents a functional unit of value to an actor, not all use cases need to be directly associated with an actor.
2. It is generally not recommended to name use cases from the perspective of actors.
4. A use case diagram for the audio and video store system.
5. Four relationships in a use case diagram
1. Association: Establish a channel for participants to communicate with the use case
2. Dependency: One use case is affected by another use case.
3. Contain: Base USE CASE diagram The behavior of this use case contains the behavior of another use case
4. Inheritance: An extension use case is an extension of the base use case,
5. Generalization: It exists between Actors. For example, the math teacher is the generalization of the teacher, from the special to the general.