《敏捷建模》PPT课件.ppt

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1、Systems Analysis and Design in a Changing World,4th Edition,1,Systems Analysis and Design in a Changing World,Fourth Edition,Systems Analysis and Design in a Changing World,4th Edition,2,Learning Objectives,Explain the purpose and various phases of the systems development life cycle(SDLC)Explain whe

2、n to use an adaptive approach to the SDLC in place of a more predictive traditional SDLCExplain the differences between a model,a tool,a technique,and a methodologyDescribe the two overall approaches used to develop information systems:the traditional method and the object-oriented method,Systems An

3、alysis and Design in a Changing World,4th Edition,3,Learning Objectives(continued),Describe some of the variations of the systems development life cycle(SDLC)Describe the key features of current trends in systems development:the Unified Process(UP),Extreme Programming(XP),Agile Modeling,and ScrumExp

4、lain how automated tools are used in system development,敏捷建模,Systems Analysis and Design in a Changing World,4th Edition,4,Overview,System development projectPlanned undertaking with fixed beginning and endProduces desired result or product Can be a large job with thousands of hours of effort or a s

5、mall one-month projectSuccessful development projectProvides a detailed plan to followOrganized,methodical sequence of tasks and activitiesProduces reliable,robust,and efficient system,Systems Analysis and Design in a Changing World,4th Edition,5,The Systems Development Lifecycle(SDLC),Systems devel

6、opment life cycle(SDLC)Provides overall framework for managing systems development processTwo main approaches to SDLCPredictive approach assumes project can be planned out in advanceAdaptive approach more flexible,assumes project cannot be planned out in advanceAll projects use some variation of SDL

7、C,Systems Analysis and Design in a Changing World,4th Edition,6,Choosing the Predictive vs.Adaptive Approach to the SDLC(Figure 2-1),Systems Analysis and Design in a Changing World,4th Edition,7,Traditional Predictive Approach to the SDLC,Project planning initiate,ensure feasibility,plan schedule,ob

8、tain approval for projectAnalysis understand business needs and processing requirementsDesign define solution system based on requirements and analysis decisionsImplementation construct,test,train users,and install new systemSupport 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,Systems A

9、nalysis and Design in a Changing World,4th Edition,8,Information System Development Phases,Systems Analysis and Design in a Changing World,4th Edition,9,SDLC and Problem Solving,Similar to problem-solving approach in Chapter 1Organization recognizes problem(project planning)Project team investigates

10、,understands problem and solution requirements(analysis)Solution is specified in detail(design)System that solves problem is built and installed(implementation)System used,maintained,and enhanced to continue to provide intended benefits(support),Systems Analysis and Design in a Changing World,4th Ed

11、ition,10,“Waterfall”Approach to the SDLC,Systems Analysis and Design in a Changing World,4th Edition,11,1.瀑布模型(Waterfall Model),可行性研究与计划,需求分析,设计,编码,运行维护,测试,定义阶段,开发阶段,维护阶段,Systems Analysis and Design in a Changing World,4th Edition,12,Modified Waterfall Approachwith Overlapping Phases(Figure 2-5),Sys

12、tems Analysis and Design in a Changing World,4th Edition,13,Newer Adaptive Approaches to the SDLC,Based on spiral modelProject cycles through development activities over and over until project is completePrototype created by end of each cycleFocuses on mitigating riskIteration Work activities are re

13、peated Each iteration refines previous resultApproach assumes no one gets it right the first timeThere are a series of mini projects for each iteration,Systems Analysis and Design in a Changing World,4th Edition,14,The Spiral Life Cycle Model(Figure 2-6),Systems Analysis and Design in a Changing Wor

14、ld,4th Edition,15,Iteration of System Development Activities(Figure 2-7),Systems Analysis and Design in a Changing World,4th Edition,16,采用原型模型的软件生存周期,分析定义系统需求,生成原型,系统设计,程序设计,编码,测试,运 行和维护,原型化,含原型化的软件生存期,Systems Analysis and Design in a Changing World,4th Edition,17,建造/修改 原型,用户测试运行原型,听取用 户意见,原型范型,Syst

15、ems Analysis and Design in a Changing World,4th Edition,18,螺旋模型,风险分析,工程实施,用户通信,用户评估,产品维护项目,产品增强项目,新产品开发项目,概念开发项目,计划,建造及发布,Systems Analysis and Design in a Changing World,4th Edition,19,Activities of Each SDLC Phase,Predictive or adaptive approach use SDLCActivities of each“phase”are similarPhases ar

16、e not always sequentialPhases can overlapActivities across phases can be done within an iteration,Systems Analysis and Design in a Changing World,4th Edition,20,Activities of Planning Phase of SDLC,Define business problem and scopeProduce detailed project schedule Confirm project feasibility Economi

17、c,organizational,technical,resource,and scheduleStaff the project(resource management)Launch project official announcement,准确定义业务及解决方案的范围,Systems Analysis and Design in a Changing World,4th Edition,21,Activities of Analysis Phase of SDLC,Gather information to learn problem domainDefine system requir

18、ementsBuild prototypes for discovery of requirementsPrioritize requirementsGenerate and evaluate alternativesReview recommendations with management,了解客户并详述需求,Systems Analysis and Design in a Changing World,4th Edition,22,Activities of Design Phase of SDLC,Design and integrate the networkDesign the a

19、pplication architectureDesign the user interfacesDesign the system interfacesDesign and integrate the databasePrototype for design detailsDesign and integrate system controls,Systems Analysis and Design in a Changing World,4th Edition,23,Activities of Implementation Phase of SDLC,Construct software

20、componentsVerify and test Convert dataTrain users and document the systemInstall the system,Systems Analysis and Design in a Changing World,4th Edition,24,Activities of Support Phase of SDLC,Maintain systemSmall patches,repairs,and updatesEnhance systemSmall upgrades or enhancements to expand system

21、 capabilitiesLarger enhancements may require separate development projectSupport usersHelp desk and/or support team,Systems Analysis and Design in a Changing World,4th Edition,25,Methodologies and Models,MethodologiesComprehensive guidelines to follow for completing every SDLC activityCollection of

22、models,tools,and techniquesModelsRepresentation of an important aspect of real world,but not same as real thingAbstraction used to separate out aspectDiagrams and chartsProject planning and budgeting aids,Systems Analysis and Design in a Changing World,4th Edition,26,Some Models Used in System Devel

23、opment,Systems Analysis and Design in a Changing World,4th Edition,27,Tools and Techniques,ToolsSoftware support that helps create models or other required project components Range from simple drawing programs to complex CASE tools to project management softwareTechniquesCollection of guidelines tha

24、t help analysts complete a system development activity or taskCan be step-by-step instructions or just general advice,Systems Analysis and Design in a Changing World,4th Edition,28,Some Tools Used in System Development,Systems Analysis and Design in a Changing World,4th Edition,29,Some Techniques Us

25、ed in System Development,Systems Analysis and Design in a Changing World,4th Edition,30,Relationships Among Components of a Methodology,Systems Analysis and Design in a Changing World,4th Edition,31,Two Approaches to System Development,Traditional approach Also called structured system developmentSt

26、ructured analysis and design technique(SADT)Includes information engineering(IE)Object-oriented approachAlso called OOA,OOD,and OOPViews information system as collection of interacting objects that work together to accomplish tasks,Systems Analysis and Design in a Changing World,4th Edition,32,Tradi

27、tional Approach,Structured programmingImproves computer program qualityAllows other programmers to easily read and modify codeEach program module has one beginning and one endingThree programming constructs(sequence,decision,repetition),Systems Analysis and Design in a Changing World,4th Edition,33,

28、Three Structured Programming Constructs,Systems Analysis and Design in a Changing World,4th Edition,34,Top-Down Programming,Divides complex programs into hierarchy of modulesThe module at top controls execution by“calling”lower level modulesModular programming Similar to top-down programming One pro

29、gram calls other programs to work together as single system,Systems Analysis and Design in a Changing World,4th Edition,35,Top-Down or Modular Programming,Systems Analysis and Design in a Changing World,4th Edition,36,Structured Design,Technique developed to provide design guidelines What set of pro

30、grams should beWhat program should accomplishHow programs should be organized into a hierarchyModules are shown with structure chartMain principle of program modulesLoosely coupled module is independent of other modulesHighly cohesive module has one clear task,Systems Analysis and Design in a Changi

31、ng World,4th Edition,37,Structure Chart Created Using Structured Design Technique,Systems Analysis and Design in a Changing World,4th Edition,38,Structured Analysis,Define what system needs to do(processing requirements)Define data system needs to store and use(data requirements)Define inputs and ou

32、tputsDefine how functions work together to accomplish tasksData flow diagrams(DFD)and entity relationship diagrams(ERD)show results of structured analysis,Systems Analysis and Design in a Changing World,4th Edition,39,Data Flow Diagram(DFD)Created Using Structured Analysis Technique(Figure 2-15),Sys

33、tems Analysis and Design in a Changing World,4th Edition,40,Entity-Relationship Diagram(ERD)Created Using Structured Analysis Technique,Systems Analysis and Design in a Changing World,4th Edition,41,Structured Analysis Leads to Structured Design and Structured Programming(Figure 2-17),Systems Analys

34、is and Design in a Changing World,4th Edition,42,Information Engineering(IE),Refinement to structured developmentMethodology with strategic planning,data modeling,automated tools focusMore rigorous and complete than SADTIndustry merged key concepts from structured development and information enginee

35、ring approaches into traditional approach,Systems Analysis and Design in a Changing World,4th Edition,43,Object-Oriented Approach,Completely different approach to information systemsViews information system as collection of interacting objects that work together to accomplish tasksObjects things in

36、computer system that can respond to messagesConceptually,no processes,programs,data entities,or files are defined just objectsOO languages:Java,C+,C#.NET,VB.NET,Systems Analysis and Design in a Changing World,4th Edition,44,Object-Oriented Approach to Systems,Systems Analysis and Design in a Changin

37、g World,4th Edition,45,Object-Oriented Approach(continued),Object-oriented analysis(OOA)Defines types of objects users deal withShows use cases are required to complete tasksObject-oriented design(OOD)Defines object types needed to communicate with people and devices in systemShows how objects inter

38、act to complete tasksRefines each type of object for implementation with specific language of environmentObject-oriented programming(OOP)Writing statements in programming language to define what each type of object does,Systems Analysis and Design in a Changing World,4th Edition,46,Class Diagram Cre

39、ated During OO Analysis,Systems Analysis and Design in a Changing World,4th Edition,47,SDLC Variations,Many variations of SDLC in practiceBased on variation of names for phases No matter which one,activities/tasks are similarSome increase emphasis on peopleUser-centered design,participatory designSo

40、ciotechnical systemsSome increase speed of developmentRapid application development(RAD)Prototyping,Systems Analysis and Design in a Changing World,4th Edition,48,Life Cycles with Different Names for Phases(Figure 2-20),Systems Analysis and Design in a Changing World,4th Edition,49,Current Trends in

41、 Development,More adaptive approachesThe Unified Process(UP)Extreme Programming(XP)Agile ModelingScrumDetails on each in Chapter 16,Systems Analysis and Design in a Changing World,4th Edition,50,The Unified Process(UP),Object-oriented development approachOffered by IBM/Rational Booch,Rumbaugh,Jacobs

42、onUnified Modeling Language(UML)used primarily for modeling UML can be used with any OO methodologyUP defines four life cycle phases Inception,elaboration,construction,transition,Systems Analysis and Design in a Changing World,4th Edition,51,The Unified Process(UP)(continued),Reinforces six best pra

43、cticesDevelop iterativelyDefine and manage system requirementsUse component architecturesCreate visual modelsVerify qualityControl changes,Systems Analysis and Design in a Changing World,4th Edition,52,Extreme Programming(XP),Recent,lightweight,development approach to keep process simple and efficie

44、ntDescribes system support needed and required system functionality through informal user storiesHas users describe acceptance tests to demonstrate defined outcomesRelies on continuous testing and integration,heavy user involvement,programming done by small teams,Systems Analysis and Design in a Cha

45、nging World,4th Edition,53,Agile Modeling,Hybrid of XP and UP(Scott Ambler);has more models than XP,fewer documents than UPInteractive and Incremental Modeling Apply right modelsCreate several models in parallelModel in small incrementsTeamworkGet active stakeholder participationEncourage collective

46、 ownershipModel with others and display models publicly,Systems Analysis and Design in a Changing World,4th Edition,54,Agile Modeling(continued),SimplicityUse simple contentDepict models simplyUse simplest modeling toolsValidationConsider testabilityProve model is right with code,Systems Analysis an

47、d Design in a Changing World,4th Edition,55,Scrum,For highly adaptive project needsRespond to situation as rapidly as possibleScrum refers to rugby gameBoth are quick,agile,and self-organizingTeam retains control over project Values individuals over processes,Systems Analysis and Design in a Changin

48、g World,4th Edition,56,Tools to Support System Development,Computer-aided system engineering(CASE)Automated tools to improve the speed and quality of system development workContains database of information about system called repositoryUpper CASE support for analysis and designLower CASE support for

49、 implementationICASE integrated CASE toolsNow called visual modeling tools,integrated application development tools,and round-trip engineering tools,Systems Analysis and Design in a Changing World,4th Edition,57,CASE Tool Repository Contains All System Information,Systems Analysis and Design in a Ch

50、anging World,4th Edition,58,Summary,System development projects are organized around the systems development life cycle(SDLC)Some projects use a predictive approach to the SDLC,and others use a more adaptive approach to the SDLC SDLC phases include project planning,analysis,design,implementation,and