《敏捷建模》PPT课件.ppt

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1、2 Systems Analysis and Design in a Changing World,Fourth Edition1Systems Analysis and Design in a Changing World,4th Edition2Learning ObjectivesuExplain the purpose and various phases of the systems development life cycle(SDLC)uExplain when to use an adaptive approach to the SDLC in place of a more

2、predictive traditional SDLCuExplain the differences between a model,a tool,a technique,and a methodologyuDescribe the two overall approaches used to develop information systems:the traditional method and the object-oriented method2Systems Analysis and Design in a Changing World,4th Edition2Learning

3、Objectives(continued)uDescribe some of the variations of the systems development life cycle(SDLC)uDescribe the key features of current trends in systems development:the Unified Process(UP),Extreme Programming(XP),Agile Modeling,and ScrumuExplain how automated tools are used in system development敏捷建模

4、3Systems Analysis and Design in a Changing World,4th Edition2OverviewuSystem development projectlPlanned undertaking with fixed beginning and endlProduces desired result or product lCan be a large job with thousands of hours of effort or a small one-month projectuSuccessful development projectlProvi

5、des a detailed plan to followlOrganized,methodical sequence of tasks and activitieslProduces reliable,robust,and efficient system4Systems Analysis and Design in a Changing World,4th Edition2The Systems Development Lifecycle(SDLC)uSystems development life cycle(SDLC)lProvides overall framework for ma

6、naging systems development processuTwo main approaches to SDLClPredictive approach assumes project can be planned out in advancelAdaptive approach more flexible,assumes project cannot be planned out in advanceuAll projects use some variation of SDLC5Systems Analysis and Design in a Changing World,4t

7、h Edition2Choosing the Predictive vs.Adaptive Approach to the SDLC(Figure 2-1)6Systems Analysis and Design in a Changing World,4th Edition2Traditional Predictive Approach to the SDLCuProject planning initiate,ensure feasibility,plan schedule,obtain approval for projectuAnalysis understand business n

8、eeds and processing requirementsuDesign define solution system based on requirements and analysis decisionsuImplementation construct,test,train users,and install new systemuSupport keep system running and improve理解待解决的业务及定义业务需求开发程序结构和算法7Systems Analysis and Design in a Changing World,4th Edition2Inf

9、ormation System Development Phases8Systems Analysis and Design in a Changing World,4th Edition2SDLC and Problem SolvinguSimilar to problem-solving approach in Chapter 1lOrganization recognizes problem(project planning)lProject team investigates,understands problem and solution requirements(analysis)

10、lSolution is specified in detail(design)lSystem that solves problem is built and installed(implementation)lSystem used,maintained,and enhanced to continue to provide intended benefits(support)9Systems Analysis and Design in a Changing World,4th Edition2“Waterfall”Approach to the SDLC10Systems Analys

11、is and Design in a Changing World,4th Edition21.瀑布模型(Waterfall Model)可行性研究与计划可行性研究与计划需求分析需求分析设计设计编码编码运行维护运行维护测试测试定义定义阶段阶段开开发发阶阶段段维护阶段维护阶段11Systems Analysis and Design in a Changing World,4th Edition2Modified Waterfall Approachwith Overlapping Phases(Figure 2-5)12Systems Analysis and Design in a Chan

12、ging World,4th Edition2Newer Adaptive Approaches to the SDLCuBased on spiral modellProject cycles through development activities over and over until project is completelPrototype created by end of each cyclelFocuses on mitigating riskuIteration Work activities are repeated lEach iteration refines pr

13、evious resultlApproach assumes no one gets it right the first timelThere are a series of mini projects for each iteration13Systems Analysis and Design in a Changing World,4th Edition2The Spiral Life Cycle Model(Figure 2-6)14Systems Analysis and Design in a Changing World,4th Edition2Iteration of Sys

14、tem Development Activities(Figure 2-7)15Systems Analysis and Design in a Changing World,4th Edition2采用原型模型的软件生存周期分析定义分析定义系统需求系统需求生成生成原型原型系统系统设计设计程序程序设计设计编码编码测试测试运运 行行和维护和维护原型化原型化含原型化的含原型化的软件生存期软件生存期16Systems Analysis and Design in a Changing World,4th Edition2建造建造/修改修改 原型原型用户测试用户测试运行原型运行原型 听取用听取用 户意

15、见户意见原型范型原型范型原型范型原型范型17Systems Analysis and Design in a Changing World,4th Edition2螺旋模型风险风险分析分析工程工程实施实施用户通信用户通信用户用户评估评估产品维护项目产品维护项目产品维护项目产品维护项目产品增强项目产品增强项目产品增强项目产品增强项目新产品开发项目新产品开发项目新产品开发项目新产品开发项目概念开发项目概念开发项目概念开发项目概念开发项目计划计划计划计划建造及发布建造及发布建造及发布建造及发布18Systems Analysis and Design in a Changing World,4th

16、Edition2Activities of Each SDLC PhaseuPredictive or adaptive approach use SDLCuActivities of each“phase”are similaruPhases are not always sequentialuPhases can overlapuActivities across phases can be done within an iteration19Systems Analysis and Design in a Changing World,4th Edition2Activities of

17、Planning Phase of SDLCuDefine business problem and scopeuProduce detailed project schedule uConfirm project feasibility lEconomic,organizational,technical,resource,and scheduleuStaff the project(resource management)uLaunch project official announcement准确定义业务及解决方案的范围20Systems Analysis and Design in a

18、 Changing World,4th Edition2Activities of Analysis Phase of SDLCuGather information to learn problem domainuDefine system requirementsuBuild prototypes for discovery of requirementsuPrioritize requirementsuGenerate and evaluate alternativesuReview recommendations with management了解客户并详述需求21Systems An

19、alysis and Design in a Changing World,4th Edition2Activities of Design Phase of SDLCuDesign and integrate the networkuDesign the application architectureuDesign the user interfacesuDesign the system interfacesuDesign and integrate the databaseuPrototype for design detailsuDesign and integrate system

20、 controls22Systems Analysis and Design in a Changing World,4th Edition2Activities of Implementation Phase of SDLCuConstruct software componentsuVerify and test uConvert datauTrain users and document the systemuInstall the system23Systems Analysis and Design in a Changing World,4th Edition2Activities

21、 of Support Phase of SDLCuMaintain systemlSmall patches,repairs,and updatesuEnhance systemlSmall upgrades or enhancements to expand system capabilitieslLarger enhancements may require separate development projectuSupport userslHelp desk and/or support team24Systems Analysis and Design in a Changing

22、World,4th Edition2Methodologies and ModelsuMethodologieslComprehensive guidelines to follow for completing every SDLC activitylCollection of models,tools,and techniquesuModelslRepresentation of an important aspect of real world,but not same as real thinglAbstraction used to separate out aspectlDiagr

23、ams and chartslProject planning and budgeting aids25Systems Analysis and Design in a Changing World,4th Edition2Some Models Used in System Development26Systems Analysis and Design in a Changing World,4th Edition2Tools and TechniquesuToolslSoftware support that helps create models or other required p

24、roject components lRange from simple drawing programs to complex CASE tools to project management softwareuTechniqueslCollection of guidelines that help analysts complete a system development activity or tasklCan be step-by-step instructions or just general advice27Systems Analysis and Design in a C

25、hanging World,4th Edition2Some Tools Used in System Development28Systems Analysis and Design in a Changing World,4th Edition2Some Techniques Used in System Development 29Systems Analysis and Design in a Changing World,4th Edition2Relationships Among Components of a Methodology30Systems Analysis and

26、Design in a Changing World,4th Edition2Two Approaches to System DevelopmentuTraditional approach lAlso called structured system developmentlStructured analysis and design technique(SADT)lIncludes information engineering(IE)uObject-oriented approachlAlso called OOA,OOD,and OOPlViews information syste

27、m as collection of interacting objects that work together to accomplish tasks31Systems Analysis and Design in a Changing World,4th Edition2Traditional ApproachuStructured programminglImproves computer program qualitylAllows other programmers to easily read and modify codelEach program module has one

28、 beginning and one endinglThree programming constructs(sequence,decision,repetition)32Systems Analysis and Design in a Changing World,4th Edition2Three Structured Programming Constructs33Systems Analysis and Design in a Changing World,4th Edition2Top-Down ProgramminguDivides complex programs into hi

29、erarchy of modulesuThe module at top controls execution by“calling”lower level modulesuModular programming lSimilar to top-down programming uOne program calls other programs to work together as single system34Systems Analysis and Design in a Changing World,4th Edition2Top-Down or Modular Programming

30、35Systems Analysis and Design in a Changing World,4th Edition2Structured DesignuTechnique developed to provide design guidelines lWhat set of programs should belWhat program should accomplishlHow programs should be organized into a hierarchyuModules are shown with structure chartuMain principle of p

31、rogram moduleslLoosely coupled module is independent of other moduleslHighly cohesive module has one clear task36Systems Analysis and Design in a Changing World,4th Edition2Structure Chart Created Using Structured Design Technique37Systems Analysis and Design in a Changing World,4th Edition2Structur

32、ed AnalysisuDefine what system needs to do(processing requirements)uDefine data system needs to store and use(data requirements)uDefine inputs and outputsuDefine how functions work together to accomplish tasksuData flow diagrams(DFD)and entity relationship diagrams(ERD)show results of structured ana

33、lysis38Systems Analysis and Design in a Changing World,4th Edition2Data Flow Diagram(DFD)Created Using Structured Analysis Technique(Figure 2-15)39Systems Analysis and Design in a Changing World,4th Edition2Entity-Relationship Diagram(ERD)Created Using Structured Analysis Technique40Systems Analysis

34、 and Design in a Changing World,4th Edition2Structured Analysis Leads to Structured Design and Structured Programming(Figure 2-17)41Systems Analysis and Design in a Changing World,4th Edition2Information Engineering(IE)uRefinement to structured developmentuMethodology with strategic planning,data mo

35、deling,automated tools focusuMore rigorous and complete than SADTuIndustry merged key concepts from structured development and information engineering approaches into traditional approach42Systems Analysis and Design in a Changing World,4th Edition2Object-Oriented ApproachuCompletely different appro

36、ach to information systemsuViews information system as collection of interacting objects that work together to accomplish taskslObjects things in computer system that can respond to messageslConceptually,no processes,programs,data entities,or files are defined just objectsuOO languages:Java,C+,C#.NE

37、T,VB.NET43Systems Analysis and Design in a Changing World,4th Edition2Object-Oriented Approach to Systems 44Systems Analysis and Design in a Changing World,4th Edition2Object-Oriented Approach(continued)uObject-oriented analysis(OOA)lDefines types of objects users deal withlShows use cases are requi

38、red to complete tasksuObject-oriented design(OOD)lDefines object types needed to communicate with people and devices in systemlShows how objects interact to complete taskslRefines each type of object for implementation with specific language of environmentuObject-oriented programming(OOP)lWriting st

39、atements in programming language to define what each type of object does 45Systems Analysis and Design in a Changing World,4th Edition2Class Diagram Created During OO Analysis46Systems Analysis and Design in a Changing World,4th Edition2SDLC VariationsuMany variations of SDLC in practicelBased on va

40、riation of names for phases lNo matter which one,activities/tasks are similaruSome increase emphasis on peoplelUser-centered design,participatory designlSociotechnical systemsuSome increase speed of developmentlRapid application development(RAD)lPrototyping47Systems Analysis and Design in a Changing

41、 World,4th Edition2Life Cycles with Different Names for Phases(Figure 2-20)48Systems Analysis and Design in a Changing World,4th Edition2Current Trends in DevelopmentuMore adaptive approacheslThe Unified Process(UP)lExtreme Programming(XP)lAgile ModelinglScrumuDetails on each in Chapter 1649Systems

42、Analysis and Design in a Changing World,4th Edition2The Unified Process(UP)uObject-oriented development approachuOffered by IBM/Rational lBooch,Rumbaugh,JacobsonuUnified Modeling Language(UML)used primarily for modeling uUML can be used with any OO methodologyuUP defines four life cycle phases lInce

43、ption,elaboration,construction,transition50Systems Analysis and Design in a Changing World,4th Edition2The Unified Process(UP)(continued)uReinforces six best practiceslDevelop iterativelylDefine and manage system requirementslUse component architectureslCreate visual modelslVerify qualitylControl ch

44、anges51Systems Analysis and Design in a Changing World,4th Edition2Extreme Programming(XP)uRecent,lightweight,development approach to keep process simple and efficientuDescribes system support needed and required system functionality through informal user storiesuHas users describe acceptance tests

45、to demonstrate defined outcomesuRelies on continuous testing and integration,heavy user involvement,programming done by small teams52Systems Analysis and Design in a Changing World,4th Edition2Agile ModelinguHybrid of XP and UP(Scott Ambler);has more models than XP,fewer documents than UPuInteractiv

46、e and Incremental Modeling lApply right modelslCreate several models in parallellModel in small incrementsuTeamworklGet active stakeholder participationlEncourage collective ownershiplModel with others and display models publicly53Systems Analysis and Design in a Changing World,4th Edition2Agile Mod

47、eling(continued)uSimplicitylUse simple contentlDepict models simplylUse simplest modeling toolsuValidationlConsider testabilitylProve model is right with code54Systems Analysis and Design in a Changing World,4th Edition2ScrumuFor highly adaptive project needsuRespond to situation as rapidly as possi

48、bleuScrum refers to rugby gamelBoth are quick,agile,and self-organizinguTeam retains control over project uValues individuals over processes55Systems Analysis and Design in a Changing World,4th Edition2Tools to Support System DevelopmentuComputer-aided system engineering(CASE)lAutomated tools to imp

49、rove the speed and quality of system development worklContains database of information about system called repositoryuUpper CASE support for analysis and designuLower CASE support for implementationuICASE integrated CASE toolsuNow called visual modeling tools,integrated application development tools

50、,and round-trip engineering tools56Systems Analysis and Design in a Changing World,4th Edition2CASE Tool Repository Contains All System Information57Systems Analysis and Design in a Changing World,4th Edition2SummaryuSystem development projects are organized around the systems development life cycle