How do you identify a use case and actor?

How do you identify a use case and actor?

To identify use cases we will take the following steps:

1. Step 1: Identify candidate system actors.
2. Step 2: Identify the goals of the actors.
3. Step 3: Identify the candidate use cases.
4. Step 4: Identify the start point for each use case.
5. Step 5: Identify the end point for each use case.

Is the system an actor in a use case?

System is never an actor in a use case model. You have to think about the thing that is triggering the system under investigation to carry out a process. The system itself is dumb and cannot trigger itself into action. It can only be triggered by a user or by Time.

What is use case role?

The actor context is the set of use cases in which the actor participates. The role played by one actor in one specific use case is called “use case role”. The actor role is the composition of all the use case roles.

What is primary actor in use case?

The primary actor of a use case is the stakeholder that calls on the system to deliver one of its services. It has a goal with respect to the system – one that can be satisfied by its operation. The primary actor is often, but not always, the actor who triggers the use case.

What are three techniques used to identify use cases?

Use cases are thus, a combination of existing system functions and newly requested functions. Another technique used for identifying use cases is CRUD, an acronym for Create, Read or Report, Update and Delete.

Can there be only one actor in use case diagram?

Whatever, Actor in use case can be any person or object that will participate in some activity. So, a computer could be some sort of client who accepts phone’s commands and performs action based on it. BUT, in this case I would have User be only actor.

Is time an actor in use case diagram?

An actor can be considered as someone or something that starts a use case. Scheduled tasks are started by “time”. In this sense, “time” is an actor, because it starts a use case.

What is a use case who write use cases?

A use case is written by a business analyst who meets with each user, or actor, to write out the explicit steps in a process.

What is the difference between a scenario and a use case?

Scenarios describe the software at a high level and give a rationale for each feature of the system existing. Use cases give a detailed account of what each feature does. A description of a use case contains, beyond other things, the main scenario as well alternative and exception scenarios.

What is a secondary actor in use case?

A supporting actor (also known as a secondary actor) in a use case in an external actor that provides a service to the system under design. It might be a high-speed printer, a web service, or humans that have to do some research and get back to us.

What is difference between primary actor and secondary actor?

Actors are classified into primary actors (also called active actors) and secondary actors (also called passive actors). Primary actors initiate a use case and hence are somewhat independent. Secondary actors, on the other hand, are used by the system but they do not interact with the system on their own.