面向对象系统分析与设计.ppt

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1、面向对象系统分析与面向对象系统分析与设计设计主要内容主要内容1、系统分析与设计概论、系统分析与设计概论2、面向对象概念与术语、面向对象概念与术语3、面向对象分析与设计、面向对象分析与设计4、面向对象编程、面向对象编程5、UML面向对象设计基础面向对象设计基础6、UML面向对象开发系统分析与设计概论系统分析与设计概论(System Analysis and Design)Chapter Objectives(You should be able to)1.Define a system,information system,and automated information system.2.D

2、efine the basic components and the basic characteristics of an automated information system.3.Define system analysis and design and discuss why it is a difficult human endeavor.4.Describe the skills and activities of a system analyst.系统分析与设计概论系统分析与设计概论(System Analysis and Design)5.Describe a general

3、 model of the analysis,design,and implementation process.6.Discuss systems analysis and design as a career.7.Discuss what a system analyst does.8.Discuss systems analysis and design projects and where they come from.9.Discuss the need for creating information systems requirements specifications.系统分析

4、与设计概论系统分析与设计概论(System Analysis and Design)10.Define and describe the information systems life cycle.11.Define and describe the information system development life cycle.12.Discuss the principles used to guide system analysis and design.系统分析与设计概论系统分析与设计概论(System Analysis and Design)1.Development Proc

5、ess2.Systems planning3.Systems analysis4.System design5.Systems implementation6.Systems evolution系统分析与设计概论系统分析与设计概论(System Analysis and Design)2.Concept of System Analysis and Design What is a system?A system is a set of interrelated components,working together for a common purpose.There are two typ

6、es of systems:natural and fabricated.系统分析与设计概论系统分析与设计概论(System Analysis and Design)System Model with Six Components:systemsystemboundaryboundarycontrolscontrolsprocessingprocessinginputsinputsfeedbackfeedbackoutputsoutputs系统分析与设计概论系统分析与设计概论(System Analysis and Design)What is an information system?An

7、 information system is a type of fabricated system that is used by one or more persons to help accomplish a task or assignment.系统分析与设计概论系统分析与设计概论(System Analysis and Design)What is an information system?datadatapeoplepeopleproceduresprocedures系统分析与设计概论系统分析与设计概论(System Analysis and Design)What is an

8、automated information system?A automated information system is an information system that incorporates the use of computer hardware and software as part of the system.系统分析与设计概论系统分析与设计概论(System Analysis and Design)What is an automated information system?datadatapeoplepeoplesoftwaresoftwareproceduresp

9、rocedureshardwarehardware系统分析与设计概论系统分析与设计概论(System Analysis and Design)What are the basic characteristics of an information system?The basic characteristics that exist within an information system are data,functions,and behavior,as illustrated in the following figure.DataDataFunctionsFunctionsBehavi

10、orBehavior系统分析与设计概论系统分析与设计概论(System Analysis and Design)What are the basic characteristics of an information system?Data:input,stored,or output Function:business activity performed Behavior:the observable effects of a request 系统分析与设计概论系统分析与设计概论(System Analysis and Design)What is systems analysis and

11、 design?System analysis and design is about developing software,but it is more about developing a complete automated information system,which includes hardware,software,people,procedures,and data.These five components exist in virtually all automated information systems,although the amount of each w

12、ill vary with respect to the specific system being developed.All of these components must be considered and addressed during system analysis and design.系统分析与设计概论系统分析与设计概论(System Analysis and Design)Actors of systems analysis and design?System Analyst;System Engineer;Programmer;Architect;系统系统分析分析与设与设

13、计过计过程程系统系统分析分析与设与设计过计过程程系统分析与设计概论系统分析与设计概论(System Analysis and Design)What makes systems analysis and design such a difficult human endeavor?Seven reasons:1.Analysis problems,at their inception,have ill-defined boundaries and structure(users are not certain of what they want),and have a sufficient d

14、egree of uncertainty about the nature of the solution.系统分析与设计概论系统分析与设计概论(System Analysis and Design)What makes systems analysis and design such a difficult human endeavor?2.The solutions systems analysts come up with to solve the problems are artificial,and since they are designed by humans with dif

15、ferent backgrounds,experiences,biases,and so on,there exists an endless variety of potential solutions.That means that there is no single correct solution to a problem.Many needs and Many solutions.系统分析与设计概论系统分析与设计概论(System Analysis and Design)What makes systems analysis and design such a difficult

16、human endeavor?3.Analysis problems are dynamic.No business is standing still.Change!4.The solutions to analysis problems require interdisciplinary knowledge and skills,hence,the need for a team approach to IS development.Emphasis on the partnership concept between the user community and the IS devel

17、opers.系统分析与设计概论系统分析与设计概论(System Analysis and Design)What makes systems analysis and design such a difficult human endeavor?5.The knowledge base of the systems analysis is continually evolving.As the apprentice systems analyst progresses through the junior,associate,and senior systems analyst ranks o

18、ver time,he or she continues to learn more about business problem domains as well as improving his or her analytical skills and software development tool and technique skills.系统分析与设计概论系统分析与设计概论(System Analysis and Design)What makes systems analysis and design such a difficult human endeavor?6.The pr

19、ocess of analysis is primarily a cognitive activity in that we are asked to(1)put structure to an abstract problem domain,(2)process diverse information from a variety of users,and(3)develop a logical and consistent specification that will lead to the creation of a successful information system.7.Th

20、e People!Study human and org.behavior.Stakeholders:Players in the Systems Development TeamA stakeholder is any person who has an interest in an existing or new information system.Stakeholders can be technical or nontechnical workers.For information systems,the stakeholders can be classified as(six g

21、roups of information workers):System ownersSystem usersSystems analystsSystem designersSystem buildersIT vendors and consultantsInformation versus Knowledge WorkersInformation workers are those workers whose jobs involve the creation,collection,processing,distribution,and use of information.(In USA

22、they are so called)Knowledge workers are a subset of information workers whose responsibilities are based on a specialized body of knowledge.(College educated;Depending on information and ability to properly use and react to information)System OwnersSystem owners are the information systems sponsors

23、 and chief advocates.They are usually responsible for funding the project to develop,operate,and maintain the information system.System UsersSystem users are the people who use or are affected by the information system on a regular basiscapturing,validating,entering,responding to,storing,and exchang

24、ing data and information.A common synonym is client.Types include:Internal usersClerical and service workersTechnical and professional staffSupervisors,middle managers,and executive managersRemote and mobile users(internal but disconnected)External users(customer and other system users)System Design

25、ers and System BuildersSystem designers translate system users business requirements and constraints into technical solutions.They design the computer files,databases,inputs,outputs,screens,networks,and programs that will meet the system users requirements.System builders construct the information s

26、ystem components based on the design specifications from the system designers.In many cases,the system designer and builder for a component are one and the same.Systems AnalystsA systems analyst studies the problems and needs of an organization to determine how people,data,processes,communications,a

27、nd information technology can best accomplish improvements for the business.When information technology is used,the analyst is responsible for:The efficient capture of data from its business source,The flow of that data to the computer,The processing and storage of that data by the computer,and The

28、flow of useful and timely information back to the business and its people.Variations on the Systems Analysts TitleA business analyst is a systems analyst that specializes in business problem analysis and technology-independent requirements analysis.A programmer/analyst(or analyst/programmer)includes

29、 the responsibilities of both the computer programmer and the systems analyst.Other synonyms for systems analyst include:Systems consultantSystems architectSystems engineerInformation engineerSystems integratorProblem-Solving ScenariosTrue problem situations,either real or anticipated,that require c

30、orrective actionOpportunities to improve a situation despite the absence of complaints Directives to change a situation regardless of whether anyone has complained about the current situationGeneral Problem-Solving Approach1.Identify the problem.2.Analyze and understand the problem.3.Identify soluti

31、on requirements or expectations.4.Identify alternative solutions and decide a course of action.5.Design and implement the“best”solution.6.Evaluate the results.If the problem is not solved,return to step 1 or 2 as appropriate.Where Systems Analysts WorkIn traditional businessesWorking in traditional

32、information services organizations(permanent project teams)Working in contemporary information services organizations(dynamic project teams)In outsourcing businessesContracted to traditional businessesIn consulting businessesContracted to traditional businessesIn application software businessesBuild

33、ing software products for traditional businessesTraditional IS Services OrganizationContemporary IS Services OrganizationBusiness Trends and DriversTotal quality management(TQM)Continuous process improvement(CPI)Globalization of the economyInformation technology problems and opportunitiesYear 2000 p

34、roblem(Y2K)Euro currency directiveEnterprise resource planning(ERP)Electronic commerce(EC or E-commerce)Total Quality ManagementTotal quality management(TQM)is a comprehensive approach to facilitating quality improvements and management within a business.Information systems quality standards:ISO 900

35、1,Quality systems Model for quality assurance in design/development,production,installation,and servicing.Capability Maturity Model(CMM)is a framework to assess the maturity level of an organizations information systems development and management processes and products.It consists of five levels of

36、maturity as measured by a set of guidelines called the key process areas.The CMM Process Management ModelThe Capability Maturity Model(CMM)is a framework to assess the maturity level of an organizations information system development and management processes and products.It consists of five levels o

37、f maturity as measured by a set of guidelines called the key process areas.Level 1Initial:System development projects follow no prescribed process.Level 2Repeatable:Project management processes and practices are established to track project costs,schedules,and functionality.Level 3Defined:A standard

38、 system development process(sometimes called a“methodology”)is purchased or developed,and integrated throughout the information systems/services unit of the organization.Level 4Managed:Measurable goals for quality and productivity are established.Level 5Optimizing:The standardized system development

39、 process is continuously monitored and improved based on measures and data analysis established in Level 4.The CMM Process Management ModelLevel5OPTIMIZEDLevel4MANAGEDLevel3DEFINEDLevel2REPEATABLERISKCOMPETITIVENESSLevel1INITIALBusiness Process RedesignBusiness process redesign(BPR)is the study,anal

40、ysis,and redesign of fundamental business processes to reduce costs and/or improve value added to the business.Usually complemented by continuous process improvementContinuous Process ImprovementContinuous process improvement(CPI)is the continuous monitoring of business processes to effect small but

41、 measurable improvements to cost reduction and value added.Essentially the opposite of business process redesign;however,CPI can and frequently does complement BPR.Legacy SystemsLegacy systems are older information system applications that have become crucial to the day-to-day operation of a busines

42、s and that may use technologies considered old or outdated by current standards.Can be adversely affected by technology and economic forces:Year 2000EuroCan be replaced by alternative solutions:ERPE-CommerceEnterprise Resource PlanningAn Enterprise resource planning(ERP)software product is a fully i

43、ntegrated information system that spans most basic business functions required by a major corporation.An ERP product is built around a common database shared these business functions.Examples of ERP software vendors include.BaanJ.D.EdwardsOraclePeoplesoftSAPElectronic CommerceElectronic commerce(e-c

44、ommerce or EC)involves conducting both internal and external business over the Internet,intranets,and extranets.Electronic commerce includes the buying and selling of goods and services,the transfer of funds,and the simplification of day-to-day business processes all through digital communications.T

45、hree basic types of electronic commerce applications include:MarketingBusiness-to-consumer(B2C)Business-to-business(B2B)The Systems Analyst as a FacilitatorSkills Required by Systems AnalystsWorking knowledge of information technologyComputer programming experience and expertiseGeneral business know

46、ledgeProblem-solving skillsInterpersonal communication skillsInterpersonal relations skillsFlexibility and adaptabilityCharacter and ethicsSystems analysis and design skillsThe Ten Commandments of Computer Ethics1.Thou shalt not use a computer to harm other people.2.Thou shalt not interfere with oth

47、er peoples computer work.3.Thou shalt not snoop around in other peoples computer files.4.Thou shalt not use a computer to steal.5.Thou shalt not use a computer to bear false witness.6.Thou shalt not copy or use proprietary software for which you have not paid.7.Thou shalt not use other peoples compu

48、ter resources without authorization or proper compensation.8.Thou shalt not appropriate other peoples intellectual output.9.Thou shalt think about the social consequences of the program you are writing or the system you are designing.10.Thou shalt always use a computer in ways that insure considerat

49、ion and respect for your fellow humanComputer Ethics Source:Computer Ethics Institute Source:Computer Ethics InstituteInformation System Building BlocksInformation System Building BlocksWhat are information systems,and who are the stakeholders in the information systems game?Describe the difference

50、between data and information.Define the product called an information system,and describe the role of information technology in information systems.Differentiate between front-and back-office information systems.Describe five classes of information system applications(transaction processing,manageme