example of use case diagram with scenario online ordering system

Extract these and note them as common course use cases. Look for commonalities among the use cases. When the basic course is described, consider alternate courses of events and add those to 'extend' the use case. Describe it in terms of what the user does and what the system does in response that the user should be aware of.

Each thing the use does on the site becomes a use case.įor each use case, decide on the normal course of events when that user is using the site.ĭescribe the basic course in the description for the use case. Identify who is going to be using the website.ĭefine what that user wants to do on the site. Kenworthy (1997) outlines the following steps: Write the steps in a use case in an easy-to-understand narrative. These exceptions are what happen when things go wrong at the system level.

Alternative paths – these paths are a variation on the main theme.

Main success scenarios – use case in which nothing goes wrong.

Triggers – this is the event that causes the use case to be initiated.

Preconditions – what must be true or happen before and after the use case runs.Primary Actor – stakeholder who initiates an interaction with the system to achieve a goal.Stakeholder – someone or something with vested interests in the behavior of the system under discussion (SUD).Actor – anyone or anything that performs a behavior (who is using the system).Depending on how in depth and complex you want or need to get, use cases describe a combination of the following elements:

Example of use case diagram with scenario online ordering system