Use Cases

Use cases model typical user interaction with the solution that you are designing, and describe the complete flow of an operation from the perspective of an end user. Prioritizing the design around a complete set of use cases ensures a continual focus on the delivery of expected functionality. Use cases are the principal input to logical design.

Assign relative weights to use cases, with the highest weighted use cases representing the most common user tasks. The weighting of use cases allows you to focus your design decisions on the system services that are used the most.

Use cases can be described at two levels.

• Use-case reports. Descriptions of individual use cases, including primary and alternative flows of events.

• Use-case diagrams. Diagrams depicting the relationships among actors and the use cases, presenting a more formal organization of the flow of events. Use-case diagrams are useful to model long or complex use cases. Typically, you use Unified Modeling Language (UML) standards to draw use case diagrams.