专业英语翻译unit-4综述课件

Unit4

Developingalogicaldata-flowdiagramofthecurrentsystem

SpecifyingprocesslogicusingdecisiontreesandtablesOutlineManagementInformationSystemsDevelopment

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QuestionsforDiscussion

TranslationforReferenceStructuredSystemsAnalysisandDesign参考译文

Themajorobjectiveofstructuredsystemanalysisanddesignistodeterminetheexactsystemrequirementssothatthe“right”systemisdesigned.Thestructuredapproachemploysaseriesofgraphictoolsandtechniquesthattheusercanfullyunderstand.Thismethodenablesanalyststocatcherrorsinanalysisbeforetheybecomeinputsintothedesignandsubsequentphasesofthesystemsdevelopmentprocess.1Ifanerroriscaughtduringtheanalysisphaseofaproject,thecostofcorrectingitismanytimeslowerthanthecostofcorrectingthesameerroroncethesystemhasbeendesignedandisinoperation.Forexample,ifanecessarydataelementisnotidentifiedduringtheanalysisphase,itmaybeleftoutofsystemfilesduringthedesignphase.参考译文2

Oncethesystemisinoperation,ausermaynoticethatcertaininformationismissingfromareport.Thedesignermaylookintothesituationandfindoutthatadataelementismissingfromamasterfile.参考译文3

Redesigningthefileandthereportwouldtakemuchmoretimethanaddingthedataelementtoadatadictionarytheanalysisphaseoftheproject.Theprocessofstructuredsystemsanalysishelpsanalystscatcherrorsearly.参考译文4

Insteadofgivinguserspagesofsystemspecificationsthattheycannotunderstand,thestructuredsystemsanalysisprocessusestoolsthatdepictalogicalmodelofthecurrentsystemandoftheproposedsystemthattheusercanclearlyunderstand.参考译文本句的主句中宾语tools，带有一个thatdepictalogicalmodel……直到整句话的句末的定语从句。在这个定语从句中又有一个thattheusercanclearlyunderstand定语从句修饰alogicalmodel。insteadof介词词组+n./ing

相当于副词，在句中作状语。常用于句首或句末，意思是“代替”、“顶替”(=inplaceofthat)。5参考译文Thestructuredapproachtosystemsdevelopmentiscomparedtothetraditionalapproachintable4.1.Thetraditionalapproachcallsforstudyingthecurrentsystem,includingitsdatafiles,reports,procedures,anddecisions,anddevelopinganautomatedversionofthesystem.Althoughthisapproachisefficient,thereisatendencytoautomatetheinefficienciesofthecurrentsystem.6

Reportscouldbeproducedfornoreasoninthecurrentsituation.Informationaboutapplicantscouldbeincomplete,outofdate,orsimplyinaccurate.Ifthecurrentsystemisautomated,manyoftheseproblemscouldbeleftundetected.参考译文7

Incontrast,inthestructuredapproachtosystemsanalysisanddesign,theanalystcollectsinformationaboutcurrentprocedures,informationflows,decision-makingprocesses,andreportsandbuildsalogicalmodelofthecurrentsituation,usingatoolcalledthelogicaldata-flowdiagram.参考译文8参考译文TraditionalApproachStructuredApproachStudythecurrentphysicalsystemDeviseanewphysicalsystemStudythecurrentphysicalsystemBuildthecurrentlogicalsystemAnalyzetheobjectivesofthenewsystemDeriveanewlogicalsystemDraftalternativedesignsFinalizethenewphysicalsystemTable4.1TheStructuredApproachToSystemsDevelopmentIsComparedToTheTraditionalApproach9参考译文

Thedata-flowdiagramisusedbecauseitdepictslogicalbusinessprocesses,informationrequirements,andinformationflows,notthephysicalviewoftheseelementsofthesystem.Theuserdoesn’tneedtoknowifpersonnelrecordsarestoredinatapefile,adiskfile,orpaperfiles.10Thesearephysicaltypesofstoragemedia.Thechoiceofwhethertostorepersonnelrecordsinadiskortapefileisatechnicaldesigndecisionthatthesystemsdesignershouldmake.Theuserdoesn’tneedtomaketechnicaldesigndecisions.However,theusershouldhaveanopportunitytoseealogicalviewofthedata.Inalogicaldata-flowdiagram,personnelrecordsaredepictedasapersonneldatastore,notintheirphysicalrepresentation.参考译文11参考译文

Thelogicaldata-flowdiagramprovidesagraphicmodelofthecurrentsystemandcanbeusedtoanalyzeareasofimprovementandtodevelopobjectiveforthenewsystem.Theseobjectivesshouldbevisualizedintermsofthebusinessresultsthatneedtobeachievedinthedesignofanewsystem.12

Majormodificationsincurrentprocedures,informationneeds,anddecision-makingprocesses,allofwhicharedesignedtoaccomplishdesiredobjectives,arebuiltintothemodelofthenewlogicalsystemthatisgraphicallydepictedintheproposedlogicalsystemdata-flowdiagram.参考译文主句的主语Majormodifications带有一个由allofwhich……desiredobjectives,引导的非限制性定语从句。主句的宾语themodelof……带有一个thatisgraphicallydepicted……直到句末的定语从句修饰它。13

Thelogicaldata-lowdiagramoftheproposedsystembecomesthebasisfordevelopingandevaluatingalternativedesignoptionsfortheproposedsystem.Systemsdesignalternativescouldincludemainframe-basedbatchandon-linesystems,andrangeofsoftwaretosupporttheseconfigurations,includingsoftwaredevelopedin-house,packageprograms,andsoftwaredevelopedusingfourth-generationlanguages.参考译文14Oncethebestdesignalternativehasbeenselected,thedetaileddesignandimplementationoftheproposedsystemcanbegin.Thisprocessinvolvesdesigningoutputandinputspecifications,filerequirements,andcontrolprocedures.Thesetechnicaltasksarelargelytheresponsibilityofinformationsystemsprofessionals.参考译文15参考译文

Developingalogicaldata-flowdiagramofthecurrentsystemThesystemsanalystcollectedusers’informationfrominterviewsandotherdatacollectioneffortstodevelopalogicaldata-flowdiagramofthepresentsystem.Alogicaldata-flowdiagramillustratessystemprocesses,informationflows,anddatarequirementsusingeasy-to-understandgraphicsymbol.（seefigure4.1）16参考译文flowofdatasourceordestinationprocessthattransformsflowofdatasquareroundedrectangleopen-endedrectanglestoreofdataarrowFigure4.1GraphicSymbol17参考译文

The“externalentity”(square)depictsasourceoradestinationofdata.Itoftenspecifiestheboundaryofthesystem.Processes(roundedrectangle)identifythemajoractivitiesofasystem,suchasverifycustomercreditorsendinvoicetocustomer.18Theyareusuallybestdescribedusingactionverbssuchascreate,produce,compute,determine,orverify.Datastoresarethelogicalrepositoriesofdatathatareusedthroughoutthesystem.参考译文19Dataaboutcustomers,vendors,shipments,andsuppliersmayallbehousedindatastores.Data-flowsrepresentdataorinformationthatisbeingtransmittedfromprocesstoprocess,fromanexternalentitytoaprocess,orfromaprocessintoadatastore.参考译文20Thebestwaytounderstandhowadata-flowdiagramworksistoviewone.Figure4.2illustratesasimpledata-flowdiagramshowingorderprocessing,purchasing,receive,accountpayable,andaccountsreceivableactivities.参考译文21

Thedata-flowdiagramgraphicallydepictswhathappenswhenacustomersendsinanorderforapartorder.Thepartordergoesintoaverify-orders-as-validprocess.

Whichinvolvescheckingcustomercreditstatusagainstacustomerdatastoreandcheckingfortheavailabilityofthepartbeingorderedinapartdatastore.Iftheorderisvalidated,itistemporarilystoredinapendingordersdatastore.参考译文本句话主句的宾语是process，后面接的是which引导的定语从句修饰它。在这个定语从句中checking动名词作involves的宾语，customercreditstatus…和fortheavailability…分别作checking的宾语补足语。22

Onereasonforcreatingthispendingordersdatastoreistoaccumulateenoughorderstoreceiveaquantitydiscountfromasupplier.Batchingalltheorderstoaparticularsupplieralsominimizesthepaperworkinvolvedinpreparingpurchaseordersforthesupplier.参考译文23Afterthependingordershavebeenheldforagiveninterval,theyareusedtopreparepurchaseorderstosuppliers.Thisprocessusestwodatastores:asuppliersdatastore,whichisusedtoobtainshesupplier’saddress,andapurchaseordersdatastore,whichisusedtofileacopyofthepurchaseorderbeingsenttothesupplier.参考译文24参考译文

Thesuppliershipsthepartstothecompanyalongwithshipmentadviceindicatingthecontentsoftheshipment.

Intheverify-shipment-correctprocess,thecompanychecksthepurchaseorderdatastoretomakesurethattheshipmentcontainseverythingthatwasordered.本句中主句的谓语动词是checks，tomakesure动词不定式做目的状语，后跟that引导的宾语从句。在宾语从句中有一个that引导的定语从句thatwasordered，修饰中心词thatwasordered。25

Ifthecompanyhasreceivedthecorrectshipment,itcanverifytheaccuracyoftheinvoicethathasbeensentbythesupplier,updatetheaccountspayabledatastore,andprepareavendorpaymenttothesupplier.参考译文26Whenashipmentisreceived,partsareassignedtospecificordersandindividualcustomerordersareassembled.Ashippingnoteandaninvoicearesenttothecustomer,andtheinvoiceamountisusedtoupdateanaccountreceivabledatastoreforthatcustomer.Whenthecustomerreceivestheinvoice,paymentismadeandappliedtotheaccountsreceivablebalance.参考译文27

Thissystemisfairlyeasytounderstandwiththegraphictechniquesofalogicaldata-flowdiagram.Theusershouldbeabletodetectanymissingproceduresordatarequirement.参考译文28Theoveralllogicaldata-flowdiagramhasanumberofsubsystems,includingorderprocessing,purchasing,accountsreceivable,andaccountspayable.Thedata-flowdiagramhelpsusersandanalystsvisualizetherelationshipsamongthesesubsystems.参考译文29参考译文

Theoutputsofsomeofthesubsystems,forexample,becomeinputsintoothersubsystems.Pendingorders,whichareoutputsoftheorderprocessingsubsystem,becomeinputsintoboththepurchasingandorderfillingsubsystems.30

Thepurchasingsubsystemproducesoutputsthatbecomeinputsintotheaccountspayablesubsystem.Understandingtheserelationshipsisimportantbecausedatarequirementsneedtobevisualizedonasystem-widebasis.Thedata-flowdiagraminfigure4.2showsasystemwithoutanyparticularflaws.参考译文31参考译文Figure4.2TheData-FlowDiagram32参考译文

Specifyingprocesslogicusingdecisiontreesandtables

Onnewprocedurethereliablefinancecompany(RFC)wanttointroduceisdiscountpolicyforloanapplicantswithexceptionallygoodcredithistories.Thispolicymightbeasfollows:

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Theinterestratediscounttoclientswitha“AAA”creditratingis2percentagepoints(e.g.，8percentto6percent).Customerswitha“AA”creditratingget1percentdiscountonloansof$10,000ormore,0.75percentdiscountonloansof$7,500ormore,and0.50percentdiscountforloansof$5,000ormore.Loansof$10,000ormorewouldreceiveanadditional0.50percentinterestratediscountovertheregulardiscountforcustomerswiththe“AA”creditrating.参考译文34

Althoughthispolicymayappearstraightforward,initsnarrativeversionitcouldbemisinterpreted.Adecisiontreeordecisiontableisausefultoolforspecifyingthelogicofaprocesssuchasthisone.参考译文35

ThedecisiontreeanddecisiontableforRFC’sdiscountpolicyareshowninTable4-3.Adecisiontableortreeenablestheusertomakesurethatthesystemsanalysthasinterpretedabusinesspolicyorprocedurecurrently.Inturn,thesystemsanalystcanuseadecisiontableortreetoexplainthelogicofaproceduretoaprogrammer.参考译文36

参考译文C1:creditratingAAAAAC2:loanamount≥10，000≥7，500<10，000≥5，000<7，500≥10，000≥7，500<10，000≥5，000<7，500A1:2%discount╳╳╳A2:1%discount╳A3:.75%discount╳A4:.50%discount╳Table4.2RFC’sDiscountPolicy37graphic/ɡræfik/adj.绘画的;文字的;图表的;

形象的,subsequent/sʌbsikwənt/adj.&n.

随后的;连续的;后来者identify/aiˈdentifai/vt.&vi.

辨认；识别;等同于;有关联depict/diˈpikt/vt.描绘;描画;描写；描述；刻画alternative/ɔ:lˈtə:nətiv/adj.&n.两者(两者以上)择一的;替换物representation/reprɪzenˈteɪʃən/n.

表现；描述；陈述;有代理人NewWords(1)illustrate/ˈiləstreit/vt.&vi.给加插图；说明；阐明；举例说明vendor/ˈvendə/n.摊贩；卖主；卖方；自动售货validate/ˈvælɪˌdeɪt/vt.证实；使生效；批准；认可pending/ˈpendiŋ/prep.&adj.

直到；未决的即将发生的subsystem/ˈsʌbsistəm/n.子系统；分系统straight-forward/streitˈfɔ:wəd/adj.坦诚的；率直的；简单的；易懂的NewWords(2)decision-making决策data-flowdiagram数据流程图externalentity外部实体roundedrectangle圆角矩形decisiontree决策树decisiontable决策表PhrasesRFC:Thereliablefinancecompany可靠的财务公司PO:Purchaseorders采购订单AbbreviationsGiveanexampleofdifferenceinthestructuredapproachtosystemsdevelopment.Whatisdata-flowdiagram?Whatisthe“externalentity”(square)?WhatshouldAlternativesystemdesigninclude?QuestionsforDiscussionTranslationforReference结构化系统分析和设计返回原文

结构化系统分析和设计的主要目标是确定系统确切的需求，进而进行正确的系统设计。结构化方法采用了一系列图形工具和技术，这样可有利于用户充分理解。该方法能有助于分析员在分析阶段及时发现错误，避免错误被带入到设计及后续开发进程中。1返回原文

对于同一个错误，如果在项目的分析阶段被发现，纠正它的成本要比在系统设计完成并投入运转后纠正的成本低许多。例如，在分析期间，如果一个必要的数据元素没有被辨认，在设计期间，它也许会被遗漏在系统文件之外。2一旦系统投入运行，用户也许会注意到报告中缺少某些特定信息。设计人员调查后也许会发现主文件中丢失的数据元素。返回原文3与项目分析阶段向数据字典中增加数据元素相比，重新设计文件和报告所花费的时间要更多。结构化系统分析方法有助于分析人员及早发现错误。返回原文4结构化系统分析方法运用工具描绘了让用户可以清楚理解的当前系统和推荐的系统逻辑模型，而不是向用户提供他们看不懂的系统说明书。返回原文5返回原文

结构化的系统开发方法与传统的方法比较见表4.1。传统方法要求研究当前系统，包括它的数据文件、报告、程序、判断和开发一个系统的自动版本。尽管该方法效率高，但是也使目前系统的无效部分实现了自动化。6在当前情况下产生无来由的报告。申请人的信息是残缺不全，过时或者只是不精确的。如果当前系统是自动化的，许多类似问题可能被遗留下来而不能被发现。返回原文7相反，对系统采用结构化分析和设计，分析人员通过收集关于当前程序、信息流、决策过程和报告的信息，并且利用逻辑数据流程图建立反映现状的逻辑模型。返回原文8返回原文传统方法结构化方法研究当前的物理系统制定一个新的物理系统研究当前的物理系统建立当前的逻辑系统分析新系统的目标提出一个新的逻辑系统设计替代系统的草图确定新的物理系统表4.1结构化的系统开发方法与传统的方法9返回原文

数据流程图是用来描述逻辑业务流程、信息需求、信息流，而不涉及系统元素的物理视图。用户无需了解个人记录是存储在磁带文件、磁盘文件还是纸质文件中。10这些都是存储介质的物理类型。决定将个人记录存放在磁盘中还是磁带文件里属于系统设计人员应当做的一个技术设计决策。用户不需要做技术设计决策。然而，用户应该有机会看到数据的逻辑视图。在一张逻辑数据流图中，个人记录被描述为数据存储，而不以它们的物理表示法描述。返回原文11返回原文

逻辑数据流图提供当前系统的一个图表模型，可以帮助分析需要改进的区域，拓展新系统的目标。可根据在新系统设计中需要实现的业务效果，构想出这些目标。12对当前程序、信息需求和决策过程所作的重要调整，都是根据未来要实现的目标而设计的，它们被构建到新的逻辑系统中，新的逻辑系统使用数据流程图来进行描述。返回原文13返回原文

拟议系统的逻辑数据流程图成为发展和评估拟议系统备选设计方案的基础。备选系统设计方案包括基于主机的批处理和在线系统及支持这些配置的软件的可选范围，包括软件的内部开发、软件包和使用第四代语言开发的软件。14一旦选择了最佳的设计方案，就可以开始详细设计并实施所推荐的系统。这一过程涉及输出、输入规范设计、文件需求设计和控制程序设计。这些技术任务主要由信息系统专家负责。返回原文15返回原文

建立当前系统的逻辑数据流图

系统分析员通过面谈和其他数据搜集工作来搜集用户的信息，以建立当前系统的数据流程图。逻辑数据流程图使用容易理解的图形符号来解释系统处理过程、信息流动和数据需求。（见图4.1）16返回原文数据的来源或目的地转换数据流的处理数据流正方形圆角矩形半开口矩形数据存储

箭头图4.1图形符号17返回原文

“外部实体”（正方形）描绘数据的来源或目的地。它通常界定了系统的边界。处理(圆角矩形）标识系统的主要活动，例如，核查客户的信贷或发送发票给客户。18它们通常使用动词，诸如创作、生产、计算、确定或验证。数据存储器是整个系统的数据逻辑仓库。返回原文19

有关客户、卖方、运输和供应商的数据可能都被安置在数据存储器内。数据流代表数据或信息在不同的过程中进行传输，从外部实体到业务处理，或者经过一个业务处理进入数据存储器。返回原文20了解数据流程图的最佳方法是全面审视，图4.2说明了一个简单的数据流程图，显示订单处理、采购