UML Use Case Diagram Example
Here we provide two alternative examples of a business use case diagram for a Restaurant, rendered in a notation used by Rational Unified Process (RUP).
First example shows external business view of a restaurant. We can see several business actors having some needs and goals as related to the restaurant and business use cases expressing expectations of the actors from the business.
Business use case diagram for Restaurant - External view
For example, Customer wants to Have Meal, Candidate - to Apply for Job, and Contractor - to fix some appliances. Note, that we don't have such actors as Chef or Waiter. They are not external roles but part of the business we model - the Restaurant, thus - they are not actors. In terms of RUP Chef and Waiter are business workers.
Second example shows internal business view of a restaurant. In this case we can see that restaurant has several business processes represented by business use cases which provide some services to external business actors. As in the previous example, actors have some needs and goals as related to the restaurant.
This approach could be more useful to model services that the business provides to different types of customers, but reading this kind of business use case diagrams could be confusing.
For example, Customer is now connected to Serve Meal use case, Supplier - to Purchase Supplies. We have now new actor Potential Customer participating in Advertise use case by reading ads and getting some information about restaurant. At the same time, Contractor actor is gone because Repair Appliances is not a service usually provided by restaurants.
Business use case diagram for Restaurant - Internal view
Still, in this example we don't have actors as Chef or Waiter for the same reasons as before - they both are not external roles but part of the business we model.