Write effective use case reading note two

(i) people involved in software development (stakeholders) use cases to explore requirements. Write effective use cases, image specific, concise, clear expression of demand.

(ii) A clear image of the four charts in the book:
1.figure1.1 the "Hub-and-spoke" model of requirements, expressing the relationship between usecase and all requirements.
2.figure2.2 striped Trousers:scenarios succeed or fail, a metaphor for the success and failure of two parts of Scenarios.
3.figure5.1 use case levels. The use cases set reveals a hierarchy of goals---the ever-unfolding story, the three levels of a case: Summary goals,user goals,subfunctions and The image representation of its relationship.
3.figure5.2 Ask "Why" to shift levels, three levels up why and down how.

(iii) A USECASE structure template
Primary Actor
Scope
Level
Preconditons
Trigger
Main Success Scenario
Extensions
Variations

1. The use case precondition (precondition) declares the condition that the system must meet before starting the use case. Typically, a precondition is that the condition has been set by the execution of another use case.

In the simplest case, the precondition for posting a child use case in a forum is that the user is logged in.

often in a high-level use case, there are two steps without an optional path, after lowering the first level, two steps are independent of two use cases, then the previous use case is the precondition of the latter one. As in the "Patient Doctor" use case, the first step is "registered", the second step is "go to the clinic to see the doctor", then "in the clinic" use case, "registered " is its preconditions

2. One of the most common mistakes in writing preconditions is to write preconditions that are often correct but not required.

For example, the hospital emergency patients can not pre-registered, then "registered" is not "emergency patients" pre-conditions.

3, the minimum guarantee is the system to the project related personnel to make the minimum commitment, especially in the case that the target of the main performer can not be satisfied. In the event of a failure of the target, the project stakeholders agree that their interests are protected, and the minimum guarantee is the test standard for success/failure.

4. The success guarantee (success guarantee) illustrates which benefits of the project stakeholders have been met after the use case has been successfully completed, and the use case can be successful by executing the main scene or by executing an optional path. The success guarantee is usually added as a minimum guarantee: The minimum guarantee is satisfied later, and some additional conditions are true; the additional condition includes at least the target declared in the use case title.

5, the project related personnel recognized that their interests have been met, this is the success /failure of the Test standard. The best way to find a guarantee of success is to ask the question: "What will upset the project stakeholders at the end of the use case?" "The question is usually easy to answer, and then the answer is the opposite."

6. The trigger event (trigger) indicates the conditions for starting the use case.

Write effective use case reading note two