Use case diagrams in Software Engineering - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a use case diagram?

A use case diagram is a simple visual tool that shows how users (called actors) interact with a system to achieve goals. It helps understand what the system does from the user's perspective.

beginner

Who or what is an actor in a use case diagram?

An actor represents a user or another system that interacts with the system being designed. Actors are outside the system and show who uses the system's functions.

beginner

What does an oval shape represent in a use case diagram?

An oval represents a use case, which is a specific function or goal that the system performs for an actor.

intermediate

Why are use case diagrams useful in software development?

They help teams understand user needs clearly, communicate system functions simply, and plan what the system should do before building it.

intermediate

What is the difference between 'include' and 'extend' relationships in use case diagrams?

Include means one use case always uses another as part of its process. Extend means one use case adds optional or conditional behavior to another.

In a use case diagram, what does an actor represent?

A A user or external system interacting with the system

B A function inside the system

C A database storing information

D A software developer

Actors are users or external systems that interact with the system to achieve goals.

Which shape is used to represent a use case in a use case diagram?

A Rectangle

B Oval

C Triangle

D Diamond

Use cases are shown as ovals to represent system functions or goals.

What does an 'include' relationship mean in a use case diagram?

A One use case always uses another as part of its process

B A use case is replaced by another

C Two actors communicate directly

D One use case optionally adds behavior to another

'Include' means a use case always calls another use case as part of its steps.

Why are use case diagrams helpful before coding a system?

A They design the database schema

B They show detailed code logic

C They replace testing

D They help understand user needs and system functions clearly

Use case diagrams help clarify what users want and what the system should do.

Which of the following is NOT typically shown in a use case diagram?

A Actors

B Use cases

C Detailed user interface design

D System boundaries

Use case diagrams focus on interactions and goals, not detailed screen designs.

Explain what a use case diagram is and why it is important in software development.

Think about how it shows users and system functions visually.

Describe the difference between 'include' and 'extend' relationships in use case diagrams with examples.

Consider when one function always happens versus when it happens only sometimes.