Use Cases and Scenarios
A use case is a definition of a specific business objective that the system needs to accomplish. For example, in our fictitious online library system, the functionality for Relationship to Functional and System Requirements. You might here someone ask, "badz.info me about the use case of your business idea. In some of the tips below, we'll use eBay features for example use cases. . Look at the requirements management use case diagram above and you will see . What's the difference between a User Story and a Use Case?. This guide outlines how to use Enterprise Architect to rapidly . example scenario is then used to generate Test Cases and a corresponding Use Case Diagram: A UML behavior diagram that visually describes the functional requirements of a proposed system and shows the relationships between Actors and Use Cases.
The Use Cases and Scenarios can be included on a number of other diagrams to show how business processes are automated or which component realizes the Use Case.
There is also an innovative editor where the detailed steps of Use Cases and Scenarios can be created and these can be generated to documentation thus completely dispensing with the need to create Word Processor files to document Use Cases. The steps can also be automatically generated to a number of diagram types including Activity and Sequence diagrams.
The generated diagrams can be synchronized with the steps if they change and the diagrams redrawn. Scenario Builder The Scenario Builder is a productive and unique tool and editor that allows the analyst to work with the text of Use Cases and Scenarios directly inside the model. Many analysts will be familiar with creating long and voluminous Word Processor documents describing the details of Use Cases. With the Scenario Builder the descriptions and steps of Scenarios can be entered directly into the repository and linked to other elements.
Types of Use Case Use cases can be described either at an abstract level known as a business use-case or at an implementation-specific level known as a system use case.
Each of these is described in more detail below: Business Use Case - Also known as an "Abstract-Level Use Case", these use cases are written in a technology-agnostic manner, simply referring to the high-level business process being described e.
The business use case will define the sequence of actions that the business needs to perform to give a meaningful, observable result to the external entity. System Use Case - Also known as an "Implementation Use Case", these use cases are written at a lower level of detail than the business use case and refer to specific processes that will be carried out by different parts of the system.
For example a system use case might be "return book when overdue" and would describe the interactions of the various actors borrower, librarian with the system in carrying out the end-to-end process. Typically you will start by defining the high-level business use-cases, and as the system requirements get defined, they will will be "drilled-down" into one or more lower-level system use cases.
Most efficient way to write use cases
Scenarios and User Stories One related artifact is the "business scenario" or user story. These are similar to use cases in terms of what they seek to accomplish - a description of the how the system will carry out a specified business process to fulfill the stated requirements.
However unlike a use case which is a step-by-step enumeration of the tasks carried out during a process with the associated actorsa scenario is much more free-form. Once you define your use cases and actors, just go into the reporting section and click on the 'Use Case Model' report and that's it. See the image below for a sample of the use case model. The purpose of the use cases is for effective knowledge transfer from the domain expert to the software developer -- these use cases will serve as software requirements.
What's the difference between a User Story and a Use Case?
Guideline: Detail Use Cases and Scenarios
With so many engineering teams making the paradigm shift from waterfall to Agile Software Developmentpeople often get caught up in having a pure Agile process which would include the use of User Stories. So what's all of the hoopla with User Stories? What are they, how are they different from use cases, do I need them, and where do they fit in the process?
What is a User Story? Simply put, written from the context of the user as a simple statement about their feature need. They should generally have this format. While a use case is highly structured and tells a story, the User Story sets the stage by stating the need.
A User Story is the prelude to the use case by stating the need before the use case tells the story. How does the User Story fit into the process? User Stories are great as an activity in collecting and prioritizing the high level features.