本科科设计（论文）外文翻译原文：HowVisualStudio.NETGeneratesSQLStatementsforConcurrencyControlAuthor:SteveSteinVisualStudioTeamAbstract:ThispaperexaminestheSQLstatementsVisualStudio®.NETgeneratesfordifferentkindsofconcurrencycontrol,howtomodifythemforbetterperformance,andhowtogenerateastatementthatdoesnotuseconcurrencycontrol.(5printedpages).IntroductionAnyapplicationthatmighthavemultipleuserssimultaneouslyattemptingtoaccessandmodifydataneedssomeformofconcurrencycontrol.Otherwise,oneuser'schangescouldinadvertentlyoverwritemodificationsfromotherusers.ThedesigntoolsinVisualStudio.NETcancreateSQLstatementsthatusethe"checkallvalues"approachtooptimisticconcurrencyorthe"last-inwins"approachtoupdatingdata.Thispaperwillexplain:Howeachofthesestatementtypesaregenerated.HowtomodifythegeneratedSQLstatementforbetterperformance.PrerequisitesYoushouldhaveanunderstandingof:FundamentalADO.NETdataconcepts,includingdatasetsanddataadapters.Formoreinformation,seeIntroductiontoDataAccesswithADO.NET.ConcurrencycontrolbasicsandtheoptionsavailableinVisualStudio.NET.Formoreinformation,seeIntroductiontoDataConcurrencyinADO.NET.WhereAretheSQLStatements?SQLstatementsarelocatedintheCommandTextpropertyofcommandobjects.SQLcommandsareautomaticallygeneratedatdesigntimewhenconfiguringdataadapters,andatruntimewhenusingcommandbuilderobjects.Formoreinformation,seeConcurrencyandCommandBuilderObjets.beforeushaveaddressedoverlaynetworkprogrammingissues.EvenearlyoverlaynetworkConfiguringDataAdaptersDragadataadapterfromtheDatataboftheToolboxDragatablefromServerExplorerModifyinganexistingadapter,byselectingadataadapterandclickingtheConfigureDataAdapterlinkatthebottomofthePropertieswindow.CommandBuilderobjectsCommandbuilderobjectsarecreatedprogrammaticallyatruntime.Formoreinformation,see(SqlCommandBuilderorOleDbCommandBuilder)ConcurrencyandDataAdaptersWhenconfiguringdataadapterswiththeDataAdapterConfigurationWizard,youcandecidewhethertouseoptimisticconcurrencyforthegeneratedUpdateandDeletestatements.Cons