Business Analyst: What is a use case diagram?

Use case diagram — UML diagram showing system functionality.

Key elements:

• Actors — users or external systems.
• Use cases — system functions.
• System boundary — scope of system.
• Relationships — associations, includes, extends.

Example:

Relationships:

• Include — mandatory behavior.
• Extend — optional behavior.
• Generalization — inheritance.

Benefits:

• Visual representation.
• Identifies actors and functions.
• Defines system scope.