systems analysis and design third edition use case · pdf filesystems analysis and design...

PowerPoint Presentation for Dennis, W ixom, & Roth Systems Analysis and Design, 3rd EditionCopyright 2006 © John Wiley & Sons, Inc. A ll rights reserved.5 - 1

Systems Analysis and DesignSystems Analysis and DesignThird EditionThird Edition

Alan Dennis, Barbara Haley Wixom, and Roberta RothJohn Wiley & Sons, Inc.

Slides by Candace S. Garrod Red Rocks Community College


Use Case AnalysisUse Case Analysis

Chapter 5


Key IdeasUse cases are a text-based method ofdescribing and documenting complexprocessesUse cases add detail to therequirements outlined in the requirementdefinitionSystems analysts work with users todevelop use casesSystems analysts develop process anddata models later based on the usecases


Use CasesUse Cases


Roles of Use CasesA use case is a set of activities thatproduce some output resultDescribes how the system reacts to anevent that triggers the systemTrigger -- event that causes the usecase to be executedEvent-driven modeling – everything inthe system is a response to sometriggering event


Role of Use Cases

All possible responses to the event aredocumentedUse cases are helpful when the situationis complicated


Elements of a Use CaseBasic information

Name, number and brief descriptionTrigger – event that causes the use case to being

External trigger – some from outside the systemTemporal triggers – time-based occurrences

Viewpoint of the use cases should be consistentMajor inputs and outputs

Sources and destinationsGoal is to be all inclusive

DetailsSteps performed and the data inputs and outputs

PowerPoint Presentation for Dennis, W ixom, & Roth Systems Analysis and Design, 3rd EditionCopyright 2006 © John Wiley & Sons, Inc. A ll rights reserved.

Sample Use Case


Building Use CasesBuilding Use Cases


Process of Developing Use Cases

Identify the major use casesIdentify the major steps within eachuse caseIdentify elements within stepsConfirm the use caseCycle through the above stepsiteratively


Step 1: Identify the major use cases

Ask who, what, and where about the tasks and theirinputs and outputs:What are the major tasks performed?What triggers this task? What tells you to perform thistask?What information/forms/reports do you need to performthis task?Who gives you these information/forms/reports?What information/forms/reports does this produce andwhere do they go?

Start a use case form foreach use caseIf more than nine, groupinto packages

Typical Questions AskedActivities


Sample List of Events-Actions Basedon Requirements Definition


Step 2: Identify the major steps withineach use case

Ask how about each use case:How do you produce this report?How do you change the information on the report?How do you process forms?What tools do you use to do this step (e.g., onpaper, by email, by phone)?

For each use case, fillin the major stepsneeded to process theinputs and produce theoutputs



Step 3: Identify elements within steps

Ask how about each stepHow does the person know when to perform thisstep?What forms/reports/data does this step produce?What forms/reports/data does this step need?What happens when this form/report/data is notavailable?

For each step, identifyits triggers and itsinputs and outputs



Step 4: Confirm the use case

•Ask the user to execute the process using thewritten steps in the use case – that is, have theuser role-play the use case

•For each use case,validate that it iscorrect and complete



CD SELECTIONS


CD SELECTIONS


CD SELECTIONS


CD SELECTIONS


Summary

Use cases contain all theinformation needed for processmodeling, but are easier for users tocomprehendUse cases are created in aniterative cycle of steps until they areconsidered accurate and complete


Copyright © 2006John Wiley & Sons, Inc.

All rights reserved. Reproduction or translation of thiswork beyond that permitted in Section 117 of the 1976United States Copyright Act without the expresswritten permission of the copyright owner is unlawful.Request for further information should be addressed tothe Permissions Department, John Wiley & Sons, Inc.The purchaser may make back-up copies for his/herown use only and not for redistribution or resale.The Publisher assumes no responsibility for errors,omissions, or damages, caused by the use of theseprograms or from the use of the information containedherein.

systems analysis and design third edition use case · pdf filesystems analysis and design...

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