Use cases

A business use case defines a sequence of actions that a business performs that yields an observable result of value (a work output) to a particular business actor or that shows how the business responds to a business event.

A system use case is a sequence of actions that a system performs that yields an observable result of value to a particular actor (someone or something outside the system that interacts with the system).

A use-case diagram can include multiple use cases and the relationships between use cases and the persons, groups, or systems that interact to perform the use case.

Use-case specifications share the same rich-text behavior that is present in all artifacts based on the text artifact format. The specifications often include content that is based on a template or process guidance that is similar to this outline:

1. Use-case name
2. Brief description
3. Flow of events
4. Basic flow
5. Alternative flows
6. Special requirements
7. Preconditions
8. Post conditions
9. Extension points