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1、TheDATAStatement:EfficiencyTechniquesS.DavidRiba,JADETech,Inc.,Clearwater,FLABSTRACTDATASTATEMENTOVERVIEW®ThesimplestformoftheDATAstatementis:OneofthoseSASstatementsthateveryonelearnsinthefirstdayofclass,theDATAstatementrarelyDATAdsname;getsasecondlook.Howev
2、er,thisbasicstatementhasevolvedinrecentreleasesoftheSASSystem.IfWithnooptionsspecified,theDATAkeywordcausesyouhavenotlookedattheoptionsontheDATAtwoprimaryactionstooccur.TheDATAkeywordisstatementrecently,youwillprobablybesurprised.usedtosignaltotheSASSystemth
3、atanewstepisabouttobegin.WhenaDATAkeywordisThisBeginningTutorialexaminesthesyntaxoftheencountered,SASpromptlycompletesprocessingDATAstatementandthedifferentoptionsthatareonanypreviousstep,eitherDATAorPROC.Itthenvalidforusewithit.Eachoptionwillbediscussedsets
4、uptheenvironmentnecessarytoprocesstheandillustratedwithexamplesofhow(andwhen)toprogramdatastepthatfollows.usethem.Amongthetopicsthatwillbediscussedaredatasetindexing,compression,andviews.Whenadatastepbegins,theProgramDataVectorisdefined,variousbuffersareesta
5、blishedasEFFICIENCYANDTHEDATASTATEMENTnecessary,andatleastonefileisopenedtostoretheresultsoftheprocessingdefinedinthedatastep.TherearemanyoptionsthatcanbeusedtocontrolIfnonameisdefinedforthisfile,SASusesthethedefaultbehaviorsoftheDATAstatement.Thedefaultname
6、ofWORKn(WORK1,WORK2,...properuseoftheseoptionscanbeveryeffectiveinWORKn).IfanameisdefinedaftertheDATAimprovingtheefficiencyofyourSASprograms.keyword,thefileisassignedthenamethatwasAmongtheseareoptionsto:defined.Ifafilealreadyexistswiththisname,thefileisoverw
7、rittenandanewfileiscreated.ìManageDatasetVariablesìManageDatasetsThedefaultbehavioristostoretheSASdatasetfilesìControlAccesstoDataintheSASWORKlibrary.Ifatwo-levelnameisìDefineIndexesandViewsdefined(i.e.SASUSER.dsname),thenthefileisgiventhenamewhichwasdefined
8、inthesecondpartThereareadditionaloptionstotheDATAstatementofthename(dsname)andstoredinthelibrarythatwillnotbeincludedinthisTutorial.Thesedefinedinthefirstpartofthename(SASUSER).includeoptionstom
