Use Case Diagram Flashcards
(19 cards)
What is a use case diagram?
A picture that shows what a system does and who uses it.
What 3 things do use case diagrams show?
- The system. 2. The users (actors). 3. What the users can do (use cases).
What is a use case?
A task the system can do (e.g., ‘Login’ or ‘Print Report’).
What is an actor?
A person or thing that uses the system (e.g., ‘Student’ or ‘Printer’).
What’s the difference between a primary and secondary actor?
Primary: Benefits from the system. Secondary: Helps the system (e.g., a backup server).
What’s an active actor?
A user who starts a task (e.g., a student clicking ‘Submit Homework’).
How are actors and use cases connected?
With a solid line (like a friendship link).
What does ‘include’ mean in use cases?
One use case MUST use another (e.g., ‘Pay Online’ MUST include ‘Login’).
What does ‘extend’ mean in use cases?
One use case can OPTIONALLY add to another (e.g., ‘Add Discount’ extends ‘Checkout’).
What is generalization in use cases?
A parent-child relationship (e.g., ‘Print Report’ is a child of ‘Generate Document’).
What’s in a use case description?
Name, steps, what happens before/after, errors, and who’s involved.
What are system boundaries?
A box around the system to show what’s inside vs. outside.
How do you draw a use case?
As an oval (e.g., ‘Buy Product’).
How do you draw an actor?
As a stick figure (e.g., ‘Customer’).
What’s a common mistake in use case diagrams?
Putting actors inside the system box (they must stay outside!).
What’s a precondition?
What must be true before a use case runs (e.g., ‘User must be logged in’).
What’s a postcondition?
What happens after a use case finishes (e.g., ‘Order is confirmed’).
What’s an extension point?
A spot where an optional use case can add steps (e.g., ‘Apply Coupon’ during checkout).
What’s an abstract use case?
A template use case—it can’t run alone, only its children can (e.g., ‘Generate File’ is abstract; ‘Generate PDF’ is real).
