example of use case diagram with scenario online ordering system

>: one use case always involves the steps of another >: under certain conditions, a use case follows a variant Customer Loses a Tape Buy a Tape > VIP Loses a Tape >Ħ Goals of use cases Interactions that provide value to actors Line: actor communicates with or is associated with use-case Customer Loses a Tape view of system behavior from an external person’s viewpoint effective tool for validating requirements an effective communication tool basis for a test plan basis for user manual Developing the use cases in not difficult ensuring that you have them all is murder. with the system (user, sub-system, etc.) - a role played by user Note: a use case represents a complete functionality. Serve as the foundation for developing system test casesģ USE CASE MODELLING -functional reqts., analysis phase - what a system does: functions represented as use cases - Actor: external agent that interacts with the system, exchanges info.Provide the basis for identifying major classes and their relationships.Actively involve users in the requirements-gathering process.Capture the system's functional requirements from the users' perspective.The use case model consists of the collection of all actors and all use cases.Ģ Use cases help.

Scenario A sequence of steps that describe the interactions between an actor and the system. An actor is a user playing a role with respect to the system. 1 USE CASE MODELLING A use case is a scenario that describes the use of a system by an actor to accomplish a specific goal.

Example of use case diagram with scenario online ordering system