Informatica Question Answer

12/23/2015 InformaticaQuestionAnswer

http://shaninformatica.blogspot.com/ 1/71

2ndJune2012

Q1.SupposewehaveDuplicaterecordsinSourceSystemandwewanttoloadonlytheuniquerecordsintheTargetSystemeliminatingtheduplicaterows.Whatwillbetheapproach?Ans.

[http://3.bp.blogspot.com/eupPD2VLBU/T8nOyWjmZjI/AAAAAAAADIg/t5LcnEgyc/s1600/t1.PNG]

[http://3.bp.blogspot.com/BFYOJdTagiM/T8nPFWTZfaI/AAAAAAAADIo/Yg4ByC2Ld5w/s1600/t2.PNG]

LetusassumethatthesourcesystemisaRelationalDatabase.Thesourcetableishavingduplicaterows.Nowtoeliminateduplicaterecords,wecanchecktheDistinctoptionoftheSourceQualifierofthesourcetableandloadthetargetaccordingly.

SourceQualifierTransformationDISTINCTclause

NowsupposethesourcesystemisaFlatFile.HereintheSourceQualifieryouwillnotbeabletoselectthedistinctclauseasitisdisabledduetoflatfilesourcetable.HencethenextapproachmaybeweuseaSorterTransformationandchecktheDistinctoption.Whenweselectthedistinctoptionallthecolumnswilltheselectedaskeys,inascendingorderbydefault.

SorterTransformationDISTINCTclause

OtherwaystohandleduplicaterecordsinsourcebatchrunistouseanAggregatorTransformationandusingtheGroupBycheckboxontheportshavingduplicateoccurringdata.Hereyoucanhavetheflexibilitytoselectthelastorthefirstoftheduplicatecolumnvaluerecords.ApartfromthatusingDynamicLookupCacheofthetargettableandassociatingtheinputportswiththelookupportandcheckingtheInsertElseUpdateoptionwillhelptoeliminatetheduplicaterecordsinsourceandhenceloadinguniquerecordsinthetarget.

InformaticaQuestionAnswer

DeletingduplicaterowusingInformatica

DeletingduplicaterowforFLATFILEsources

DeletingDuplicateRecordUsingInformaticaAggregator

LoadingMultipleTargetTablesBasedonConditions



Q2.Supposewehavesomeserialnumbersinaflatfilesource.WewanttoloadtheserialnumbersintwotargetfilesonecontainingtheEVENserialnumbersandtheotherfilehavingtheODDones.

Ans.AftertheSourceQualifierplaceaRouterTransformation.CreatetwoGroupsnamelyEVENandODD,withfilterconditionsasMOD(SERIAL_NO,2)=0andMOD(SERIAL_NO,2)=1respectively.Thenoutputthetwogroupsintotwoflatfiletargets.

RouterTransformationGroupsTab

Q3.SupposeinourSourceTablewehavedataasgivenbelow:

StudentName Maths LifeScience PhysicalScience

Sam 100 70 80

John 75 100 85

Tom 80 100 85

WewanttoloadourTargetTableas:

StudentName SubjectName Marks

Sam Maths 100

Sam LifeScience 70

Sam PhysicalScience 80

John Maths 75

John LifeScience 100

John PhysicalScience 85

Tom Maths 80

Tom LifeScience 100

Tom PhysicalScience 85

Describeyourapproach.

Ans.HeretoconverttheRowstoColumnswehavetousetheNormalizerTransformationfollowedbyanExpressionTransformationtoDecodethecolumntakenintoconsideration.FormoredetailsonhowthemappingisperformedpleasevisitWorkingwithNormalizer[http://www.dwbiconcepts.com/basicconcept/3etl/23usinginformaticanormalizertransformation.html]

Q4.Namethetransformationswhichconvertsonetomanyrowsi.eincreasesthei/p:o/prowcount.Alsowhatisthenameofitsreversetransformation.

Ans.NormalizeraswellasRouterTransformationsaretheActivetransformationwhichcanincreasethenumberofinputrowstooutputrows.

AggregatorTransformationistheactivetransformationthatperformsthereverseaction.

Q5.Supposewehaveasourcetableandwewanttoloadthreetargettablesbasedonsourcerowssuchthatfirstrowmovestofirsttargettable,secordrowinsecondtargettable,thirdrowinthirdtargettable,fourthrowagaininfirsttargettablesoonandsoforth.Describeyourapproach.

Ans.WecanclearlyunderstandthatweneedaRoutertransformationtorouteorfiltersourcedatatothethreetargettables.Nowthequestioniswhatwillbethefilterconditions.FirstofallweneedanExpressionTransformationwherewehaveallthesourcetablecolumnsandalongwiththatwehaveanotheri/oportsayseq_num,whichisgetssequencenumbersforeachsourcerowfromtheportNextValofaSequenceGeneratorstartvalue0andincrementby1.Nowthefilterconditionforthethreeroutergroupswillbe:

MOD(SEQ_NUM,3)=1connectedto1sttargettable,MOD(SEQ_NUM,3)=2connectedto2ndtargettable,MOD(SEQ_NUM,3)=0connectedto3rdtargettable.

NormalizerRelatedQuestions



RouterTransformationGroupsTab

Q6.Supposewehavetensourceflatfilesofsamestructure.Howcanweloadallthefilesintargetdatabaseinasinglebatchrunusingasinglemapping.

Ans.Afterwecreateamappingtoloaddataintargetdatabasefromflatfiles,nextwemoveontothesessionpropertyoftheSourceQualifier.Toloadasetofsourcefilesweneedtocreateafilesayfinal.txtcontainingthesourcefaltfilenames,tenfilesinourcaseandsettheSourcefiletypeoptionasIndirect.Nextpointthisflatfilefinal.txtfullyqualifiedthroughSourcefiledirectoryandSourcefilename.

Image:SessionPropertyFlatFile[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

Q7.HowcanweimplementAggregationoperationwithoutusinganAggregatorTransformationinInformatica.

Ans.WewillusetheverybasicconceptoftheExpressionTransformationthatatatimewecanaccessthepreviousrowdataaswellasthecurrentlyprocesseddatainanexpressiontransformation.WhatweneedissimpleSorter,ExpressionandFiltertransformationtoachieveaggregationatInformaticalevel.FordetailedunderstandingvisitAggregationwithoutAggregator[http://www.dwbiconcepts.com/basicconcept/3etl/10aggregationwithoutinformaticaaggregator.html]

Q8.SupposeinourSourceTablewehavedataasgivenbelow:

StudentName SubjectName Marks

Sam Maths 100

Tom Maths 80

Sam PhysicalScience 80

John Maths 75

Sam LifeScience 70

John LifeScience 100

John PhysicalScience 85

Tom LifeScience 100

Tom PhysicalScience 85

LoadingMultipleFlatFilesusingonemapping



WewanttoloadourTargetTableas:

StudentName Maths LifeScience PhysicalScience

Sam 100 70 80

John 75 100 85

Tom 80 100 85

Describeyourapproach.

Ans.Hereourscenarioistoconvertmanyrowstoonerows,andthetransformationwhichwillhelpustoachievethisisAggregator.OurMappingwilllooklikethis:

MappingusingsorterandAggregator

WewillsortthesourcedatabasedonSTUDENT_NAMEascendingfollowedbySUBJECTascending.



SorterTransformation

NowbasedonSTUDENT_NAMEinGROUPBYclausethefollowingoutputsubjectcolumnsarepopulatedasMATHS:MAX(MARKS,SUBJECT='Maths')LIFE_SC:MAX(MARKS,SUBJECT='LifeScience')PHY_SC:MAX(MARKS,SUBJECT='PhysicalScience')

AggregatorTransformation

Q9.WhatisaSourceQualifier?WhatarethetaskswecanperformusingaSQandwhyitisanACTIVEtransformation?

Ans.ASourceQualifierisanActiveandConnectedInformaticatransformationthatreadstherowsfromarelationaldatabaseorflatfilesource.

WecanconfiguretheSQtojoin[BothINNERaswellasOUTERJOIN]dataoriginatingfromthesamesourcedatabase.WecanuseasourcefiltertoreducethenumberofrowstheIntegrationServicequeries.WecanspecifyanumberforsortedportsandtheIntegrationServiceaddsanORDERBYclausetothedefaultSQLquery.WecanchooseSelectDistinctoptionforrelationaldatabasesandtheIntegrationServiceaddsaSELECTDISTINCTclausetothedefaultSQLquery.AlsowecanwriteCustom/UsedDefinedSQLquerywhichwilloverridethedefaultqueryintheSQbychangingthedefaultsettingsofthetransformationproperties.AslowehavetheoptiontowritePreaswellasPostSQLstatementstobeexecutedbeforeandaftertheSQqueryinthesourcedatabase.

SincethetransformationprovidesuswiththepropertySelectDistinct,whentheIntegrationServiceaddsaSELECTDISTINCTclausetothedefaultSQLquery,whichinturnaffectsthenumberofrowsreturnedbytheDatabasetotheIntegrationServiceandhenceitisanActivetransformation.

Q10.WhathappenstoamappingifwealterthedatatypesbetweenSourceanditscorrespondingSourceQualifier?

Ans.TheSourceQualifiertransformationdisplaysthetransformationdatatypes.ThetransformationdatatypesdeterminehowthesourcedatabasebindsdatawhentheIntegrationServicereadsit.NowifwealterthedatatypesintheSourceQualifiertransformationorthedatatypesinthesourcedefinitionandSourceQualifiertransformationdonotmatch,theDesignermarksthemappingasinvalidwhenwesaveit.

Q11.SupposewehaveusedtheSelectDistinctandtheNumberOfSortedPortspropertyintheSQandthenweaddCustomSQLQuery.Explainwhatwillhappen.

Ans.WheneverweaddCustomSQLorSQLoverridequeryitoverridestheUserDefinedJoin,SourceFilter,Numberof

RevisitingSourceQualifierTransformation



SortedPorts,andSelectDistinctsettingsintheSourceQualifiertransformation.HenceonlytheuserdefinedSQLQuerywillbefiredinthedatabaseandalltheotheroptionswillbeignored.

Q12.DescribethesituationswherewewillusetheSourceFilter,SelectDistinctandNumberOfSortedPortspropertiesofSourceQualifiertransformation.

Ans.SourceFilteroptionisusedbasicallytoreducethenumberofrowstheIntegrationServicequeriessoastoimproveperformance.SelectDistinctoptionisusedwhenwewanttheIntegrationServicetoselectuniquevaluesfromasource,filteringoutunnecessarydataearlierinthedataflow,whichmightimproveperformance.NumberOfSortedPortsoptionisusedwhenwewantthesourcedatatobeinasortedfashionsoastousethesameinsomefollowingtransformationslikeAggregatororJoiner,thosewhenconfiguredforsortedinputwillimprovetheperformance.

Q13.WhatwillhappeniftheSELECTlistCOLUMNSintheCustomoverrideSQLQueryandtheOUTPUTPORTSorderinSQtransformationdonotmatch?

Ans.MismatchorChangingtheorderofthelistofselectedcolumnstothatoftheconnectedtransformationoutputportsmayresultissessionfailure.

Q14.WhathappensifintheSourceFilterpropertyofSQtransformationweincludekeywordWHEREsay,WHERECUSTOMERS.CUSTOMER_ID>1000.

Ans.Weusesourcefiltertoreducethenumberofsourcerecords.IfweincludethestringWHEREinthesourcefilter,theIntegrationServicefailsthesession.

Q15.DescribethescenarioswherewegoforJoinertransformationinsteadofSourceQualifiertransformation.

Ans.WhilejoiningSourceDataofheterogeneoussourcesaswellastojoinflatfileswewillusetheJoinertransformation.UsetheJoinertransformationwhenweneedtojointhefollowingtypesofsources:JoindatafromdifferentRelationalDatabases.JoindatafromdifferentFlatFiles.Joinrelationalsourcesandflatfiles.

Q16.WhatisthemaximumnumberwecanuseinNumberOfSortedPortsforSybasesourcesystem.

Ans.Sybasesupportsamaximumof16columnsinanORDERBYclause.SoifthesourceisSybase,donotsortmorethan16columns.

Q17.SupposewehavetwoSourceQualifiertransformationsSQ1andSQ2connectedtoTargettablesTGT1andTGT2respectively.HowdoyouensureTGT2isloadedafterTGT1?

Ans.IfwehavemultipleSourceQualifiertransformationsconnectedtomultipletargets,wecandesignatetheorderinwhichtheIntegrationServiceloadsdataintothetargets.IntheMappingDesigner,WeneedtoconfiguretheTargetLoadPlanbasedontheSourceQualifiertransformationsinamappingtospecifytherequiredloadingorder.

Image:TargetLoadPlan[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

TargetLoadPlanOrdering

Q18.SupposewehaveaSourceQualifiertransformationthatpopulatestwotargettables.HowdoyouensureTGT2



isloadedafterTGT1?

Ans.IntheWorkflowManager,wecanConfigureConstraintbasedloadorderingforasession.TheIntegrationServiceordersthetargetloadonarowbyrowbasis.Foreveryrowgeneratedbyanactivesource,theIntegrationServiceloadsthecorrespondingtransformedrowfirsttotheprimarykeytable,thentotheforeignkeytable.HenceifwehaveoneSourceQualifiertransformationthatprovidesdataformultipletargettableshavingprimaryandforeignkeyrelationships,wewillgoforConstraintbasedloadordering.

Image:Constraintbasedloading[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

Q19.WhatisaFilterTransformationandwhyitisanActiveone?

Ans.AFiltertransformationisanActiveandConnectedtransformationthatcanfilterrowsinamapping.OnlytherowsthatmeettheFilterConditionpassthroughtheFiltertransformationtothenexttransformationinthepipeline.TRUEandFALSEaretheimplicitreturnvaluesfromanyfilterconditionweset.IfthefilterconditionevaluatestoNULL,therowisassumedtobeFALSE.ThenumericequivalentofFALSEiszero(0)andanynonzerovalueistheequivalentofTRUE.

AsanACTIVEtransformation,theFiltertransformationmaychangethenumberofrowspassedthroughit.AfilterconditionreturnsTRUEorFALSEforeachrowthatpassesthroughthetransformation,dependingonwhetherarowmeetsthespecifiedcondition.OnlyrowsthatreturnTRUEpassthroughthistransformation.Discardedrowsdonotappearinthesessionlogorrejectfiles.

Q20.WhatisthedifferencebetweenSourceQualifiertransformationsSourceFiltertoFiltertransformation?

Ans.

SQSourceFilter FilterTransformation

SourceQualifiertransformationfiltersrowswhenreadfromasource.

Filtertransformationfiltersrowsfromwithinamapping

SourceQualifiertransformationcanonlyfilterrowsfromRelationalSources.

Filtertransformationfiltersrowscomingfromanytypeofsourcesysteminthemappinglevel.

SourceQualifierlimitstherowsetextractedfromasource.

Filtertransformationlimitstherowsetsenttoatarget.

SourceQualifierreducesthenumberofrowsusedthroughoutthemappingandhenceitprovidesbetterperformance.

Tomaximizesessionperformance,includetheFiltertransformationasclosetothesourcesinthemappingaspossibletofilteroutunwanteddataearlyintheflowofdatafromsourcestotargets.

ThefilterconditionintheSourceQualifiertransformationonlyusesstandardSQLasitrunsinthedatabase.

FilterTransformationcandefineaconditionusinganystatementortransformationfunctionthatreturnseitheraTRUEorFALSEvalue.

Q21.WhatisaJoinerTransformationandwhyitisanActiveone?

Ans.AJoinerisanActiveandConnectedtransformationusedtojoinsourcedatafromthesamesourcesystemorfromtworelatedheterogeneoussourcesresidingindifferentlocationsorfilesystems.TheJoinertransformationjoinssourceswithatleastonematchingcolumn.TheJoinertransformationusesaconditionthatmatchesoneormorepairsofcolumnsbetweenthetwosources.Thetwoinputpipelinesincludeamasterpipelineandadetailpipelineoramasterandadetailbranch.ThemasterpipelineendsattheJoinertransformation,whilethedetailpipelinecontinuestothetarget.

IntheJoinertransformation,wemustconfigurethetransformationpropertiesnamelyJoinCondition,JoinTypeandSortedInputoptiontoimproveIntegrationServiceperformance.ThejoinconditioncontainsportsfrombothinputsourcesthatmustmatchfortheIntegrationServicetojointworows.Dependingonthetypeofjoinselected,theIntegrationServiceeitheraddstherowtotheresultsetordiscardstherow.

RevisitingFilterTransformation

RevisitingJoinerTransformation



TheJoinertransformationproducesresultsetsbasedonthejointype,condition,andinputdatasources.HenceitisanActivetransformation.

Q22.StatethelimitationswherewecannotuseJoinerinthemappingpipeline.

Ans.TheJoinertransformationacceptsinputfrommosttransformations.However,followingarethelimitations:

JoinertransformationcannotbeusedwheneitheroftheinputpipelinecontainsanUpdateStrategytransformation.JoinertransformationcannotbeusedifweconnectaSequenceGeneratortransformationdirectlybeforetheJoinertransformation.

Q23.Outofthetwoinputpipelinesofajoiner,whichonewillyousetasthemasterpipeline?

Ans.Duringasessionrun,theIntegrationServicecompareseachrowofthemastersourceagainstthedetailsource.Themasteranddetailsourcesneedtobeconfiguredforoptimalperformance.

ToimproveperformanceforanUnsortedJoinertransformation,usethesourcewithfewerrowsasthemastersource.Thefeweruniquerowsinthemaster,thefeweriterationsofthejoincomparisonoccur,whichspeedsthejoinprocess.WhentheIntegrationServiceprocessesanunsortedJoinertransformation,itreadsallmasterrowsbeforeitreadsthedetailrows.TheIntegrationServiceblocksthedetailsourcewhileitcachesrowsfromthemastersource.OncetheIntegrationServicereadsandcachesallmasterrows,itunblocksthedetailsourceandreadsthedetailrows.

ToimproveperformanceforaSortedJoinertransformation,usethesourcewithfewerduplicatekeyvaluesasthemastersource.WhentheIntegrationServiceprocessesasortedJoinertransformation,itblocksdatabasedonthemappingconfigurationanditstoresfewerrowsinthecache,increasingperformance.BlockinglogicispossibleifmasteranddetailinputtotheJoinertransformationoriginatefromdifferentsources.Otherwise,itdoesnotuseblockinglogic.Instead,itstoresmorerowsinthecache.

Q24.WhatarethedifferenttypesofJoinsavailableinJoinerTransformation?

Ans.InSQL,ajoinisarelationaloperatorthatcombinesdatafrommultipletablesintoasingleresultset.TheJoinertransformationissimilartoanSQLjoinexceptthatdatacanoriginatefromdifferenttypesofsources.TheJoinertransformationsupportsthefollowingtypesofjoins:NormalMasterOuterDetailOuterFullOuter

JoinTypepropertyofJoinerTransformation



Note:Anormalormasterouterjoinperformsfasterthanafullouterordetailouterjoin.

Q25.DefinethevariousJoinTypesofJoinerTransformation.

Ans.Inanormaljoin,theIntegrationServicediscardsallrowsofdatafromthemasteranddetailsourcethatdonotmatch,basedonthejoincondition.Amasterouterjoinkeepsallrowsofdatafromthedetailsourceandthematchingrowsfromthemastersource.Itdiscardstheunmatchedrowsfromthemastersource.Adetailouterjoinkeepsallrowsofdatafromthemastersourceandthematchingrowsfromthedetailsource.Itdiscardstheunmatchedrowsfromthedetailsource.Afullouterjoinkeepsallrowsofdatafromboththemasteranddetailsources.

Q26.DescribetheimpactofnumberofjoinconditionsandjoinorderinaJoinerTransformation.

Ans.Wecandefineoneormoreconditionsbasedonequalitybetweenthespecifiedmasteranddetailsources.Bothportsinaconditionmusthavethesamedatatype.Ifweneedtousetwoportsinthejoinconditionwithnonmatchingdatatypeswemustconvertthedatatypessothattheymatch.TheDesignervalidatesdatatypesinajoincondition.Additionalportsinthejoinconditionincreasesthetimenecessarytojointwosources.

TheorderoftheportsinthejoinconditioncanimpacttheperformanceoftheJoinertransformation.Ifweusemultipleportsinthejoincondition,theIntegrationServicecomparestheportsintheorderwespecified.

NOTE:Onlyequalityoperatorisavailableinjoinerjoincondition.

Q27.HowdoesJoinertransformationtreatNULLvaluematching.

Ans.TheJoinertransformationdoesnotmatchnullvalues.Forexample,ifbothEMP_ID1andEMP_ID2containarowwithanullvalue,theIntegrationServicedoesnotconsiderthemamatchanddoesnotjointhetworows.Tojoinrowswithnullvalues,replacenullinputwithdefaultvaluesinthePortstabofthejoiner,andthenjoinonthedefaultvalues.

Note:Ifaresultsetincludesfieldsthatdonotcontaindataineitherofthesources,theJoinertransformationpopulatestheemptyfieldswithnullvalues.IfweknowthatafieldwillreturnaNULLandwedonotwanttoinsertNULLsinthetarget,setadefaultvalueonthePortstabforthecorrespondingport.

Q28.SupposeweconfigureSortertransformationsinthemasteranddetailpipelineswiththefollowingsortedportsinorder:ITEM_NO,ITEM_NAME,PRICE.Whenweconfigurethejoincondition,whataretheguidelinesweneedtofollowtomaintainthesortorder?

Ans.IfwehavesortedboththemasteranddetailpipelinesinorderoftheportssayITEM_NO,ITEM_NAMEandPRICEwemustensurethat:UseITEM_NOintheFirstJoinCondition.IfweaddaSecondJoinCondition,wemustuseITEM_NAME.IfwewanttousePRICEasaJoinConditionapartfromITEM_NO,wemustalsouseITEM_NAMEintheSecondJoinCondition.IfweskipITEM_NAMEandjoinonITEM_NOandPRICE,wewilllosetheinputsortorderandtheIntegrationServicefailsthesession.

Q29.WhatarethetransformationsthatcannotbeplacedbetweenthesortoriginandtheJoinertransformationsothatwedonotlosetheinputsortorder.

Ans.ThebestoptionistoplacetheJoinertransformationdirectlyafterthesortorigintomaintainsorteddata.HoweverdonotplaceanyofthefollowingtransformationsbetweenthesortoriginandtheJoinertransformation:

CustomUnsortedAggregatorNormalizerRankUniontransformationXMLParsertransformationXMLGeneratortransformationMapplet[ifitcontainsanyoneoftheabovementionedtransformations]

Q30.SupposewehavetheEMPtableasoursource.Inthetargetwewanttoviewthoseemployeeswhosesalaryisgreaterthanorequaltotheaveragesalaryfortheirdepartments.

Describeyourmappingapproach.Ans.OurMappingwilllooklikethis:

Image:MappingusingJoiner[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

Tostartwiththemappingweneedthefollowingtransformations:



AftertheSourcequalifieroftheEMPtableplaceaSorterTransformation.SortbasedonDEPTNOport.

SorterPortsTab

NextweplaceaSortedAggregatorTransformation.HerewewillfindouttheAVERAGESALARYforeach(GROUPBY)DEPTNO.Whenweperformthisaggregation,welosethedataforindividualemployees.Tomaintainemployeedata,wemustpassabranchofthepipelinetotheAggregatorTransformationandpassabranchwiththesamesortedsourcedatatotheJoinertransformationtomaintaintheoriginaldata.Whenwejoinbothbranchesofthepipeline,wejointheaggregateddatawiththeoriginaldata.

AggregatorPortsTab



AggregatorPropertiesTab

SonextweneedSortedJoinerTransformationtojointhesortedaggregateddatawiththeoriginaldata,basedonDEPTNO.HerewewillbetakingtheaggregatedpipelineastheMasterandoriginaldataflowasDetailPipeline.

JoinerConditionTab



JoinerPropertiesTab

AfterthatweneedaFilterTransformationtofilterouttheemployeeshavingsalarylessthanaveragesalaryfortheirdepartment.FilterCondition:SAL>=AVG_SAL

FilterPropertiesTab

LastlywehavetheTargettableinstance.

Q31.WhatisaSequenceGeneratorTransformation?

RevisitingSequenceGeneratorTransformation



Ans.ASequenceGeneratortransformationisaPassiveandConnectedtransformationthatgeneratesnumericvalues.Itisusedtocreateuniqueprimarykeyvalues,replacemissingprimarykeys,orcyclethroughasequentialrangeofnumbers.ThistransformationbydefaultcontainsONLYTwoOUTPUTportsnamelyCURRVALandNEXTVAL.Wecannoteditordeletetheseportsneitherwecannotaddportstothisuniquetransformation.Wecancreateapproximatelytwobillionuniquenumericvalueswiththewidestrangefrom1to2147483647.

Q32.DefinethePropertiesavailableinSequenceGeneratortransformationinbrief.Ans.

SequenceGeneratorProperties

Description

StartValue

StartvalueofthegeneratedsequencethatwewanttheIntegrationServicetouseifweusetheCycleoption.IfweselectCycle,theIntegrationServicecyclesbacktothisvaluewhenitreachestheendvalue.Defaultis0.

IncrementBy

DifferencebetweentwoconsecutivevaluesfromtheNEXTVALport.Defaultis1.

EndValue

MaximumvaluegeneratedbySeqGen.Afterreachingthisvaluethesessionwillfailifthesequencegeneratorisnotconfiguredtocycle.Defaultis2147483647.

CurrentValue

Currentvalueofthesequence.EnterthevaluewewanttheIntegrationServicetouseasthefirstvalueinthesequence.Defaultis1.

CycleIfselected,whentheIntegrationServicereachestheconfiguredendvalueforthesequence,itwrapsaroundandstartsthecycleagain,beginningwiththeconfiguredStartValue.

NumberofCachedValues

NumberofsequentialvaluestheIntegrationServicecachesatatime.DefaultvalueforastandardSequenceGeneratoris0.DefaultvalueforareusableSequenceGeneratoris1,000.

Reset

Restartsthesequenceatthecurrentvalueeachtimeasessionruns.ThisoptionisdisabledforreusableSequenceGeneratortransformations.

Q33.Supposewehaveasourcetablepopulatingtwotargettables.WeconnecttheNEXTVALportoftheSequenceGeneratortothesurrogatekeysofboththetargettables.WilltheSurrogatekeysinboththetargettablesbesame?Ifnothowcanweflowthesamesequencevaluesinbothofthem.Ans.WhenweconnecttheNEXTVALoutputportoftheSequenceGeneratordirectlytothesurrogatekeycolumnsofthetargettables,theSequencenumberwillnotbethesame.Ablockofsequencenumbersissenttoonetargettablessurrogatekeycolumn.ThesecondtargetsreceivesablockofsequencenumbersfromtheSequenceGeneratortransformationonlyafterthefirsttargettablereceivestheblockofsequencenumbers.Supposewehave5rowscomingfromthesource,sothetargetswillhavethesequencevaluesasTGT1(1,2,3,4,5)andTGT2(6,7,8,9,10).[TakenintoconsiderationStartValue0,Currentvalue1andIncrementby1.

Nowsupposetherequirementislikethatweneedtohavethesamesurrogatekeysinboththetargets.ThentheeasiestwaytohandlethesituationistoputanExpressionTransformationinbetweentheSequenceGeneratorandtheTargettables.TheSeqGenwillpassuniquevaluestotheexpressiontransformation,andthentherowsareroutedfromtheexpressiontransformationtothetargets.



SequenceGenerator

Q34.Supposewehave100recordscomingfromthesource.NowforatargetcolumnpopulationweusedaSequencegenerator.SupposetheCurrentValueis0andEndValueofSequencegeneratorissetto80.Whatwillhappen?Ans.EndValueisthemaximumvaluetheSequenceGeneratorwillgenerate.AfteritreachestheEndvaluethesessionfailswiththefollowingerrormessage:TT_11009SequenceGeneratorTransformation:Overflowerror.

FailingofsessioncanbehandlediftheSequenceGeneratorisconfiguredtoCyclethroughthesequence,i.e.whenevertheIntegrationServicereachestheconfiguredendvalueforthesequence,itwrapsaroundandstartsthecycleagain,beginningwiththeconfiguredStartValue.

Q35.WhatarethechangesweobservewhenwepromoteanonresuableSequenceGeneratortoaresuableone?AndwhathappensifwesettheNumberofCachedValuesto0forareusabletransformation?

Ans.WhenweconvertanonreusablesequencegeneratortoresuableoneweobservethattheNumberofCachedValuesissetto1000bydefaultAndtheResetpropertyisdisabled.

WhenwetrytosettheNumberofCachedValuespropertyofaReusableSequenceGeneratorto0intheTransformationDeveloperweencounterthefollowingerrormessage:Thenumberofcachedvaluesmustbegreaterthanzeroforreusablesequencetransformation.

Inourpreviousarticle,wetestedtheperformanceofORDERBYoperationinInformaticaandOracle[http://www.dwbiconcepts.com/advance/7general/36informaticaoraclesortperformancetest.html]andfoundthat,inourtestcondition,Oracleperformssorting14%speedierthanInformatica.ThistimewewilllookintotheJOINoperation,notonlybecauseJOINisthesinglemostimportantdatasetoperationbutalsobecauseperformanceofJOINcangivecrucialdatatoadeveloperinordertodevelopproperpushdownoptimizationmanually.Informaticaisoneoftheleadingdataintegrationtoolsintodaysworld.Morethan4,000enterprisesworldwiderelyonInformaticatoaccess,integrateandtrusttheirinformationassetswithit.Ontheotherhand,OracledatabaseisarguablythemostsuccessfulandpowerfulRDBMSsystemthatistrustedfrom1980sinallsortsofbusinessdomainandacrossallmajorplatforms.Bothofthesesystemsarebestsinthetechnologiesthattheysupport.Butwhenitcomestotheapplicationdevelopment,developersoftenfacechallengetostriketherightbalanceofoperationalloadsharingbetweenthesesystems.Thisarticlewillhelpthemtotaketheinformeddecision.

Asanapplicationdeveloper,youhavethechoiceofeitherusingjoiningsyntaxesindatabaseleveltojoinyourdataorusingJOINERTRANSFORMATIONinInformaticatoachievethesameoutcome.Thequestioniswhichsystemperformsthisfaster?

Wewillperformthesametestwith4differentdatapoints(datavolumes)andlogtheresults.Wewillstartwith1milliondataindetailtableand0.1millioninmastertable.Subsequentlywewilltestwith2million,4millionand6milliondetailtabledatavolumesand0.2million,0.4millionand0.6millionmastertabledatavolumes.Herearethedetailsofthesetupwewilluse,1.Oracle10gdatabaseasrelationalsourceandtarget2.InformaticaPowerCentre8.5asETLtool3.DatabaseandInformaticasetupondifferentphysicalserversusingHPUNIX4.Sourcedatabasetablehasnoconstraint,noindex,nodatabasestatisticsandnopartition

Whichisthefastest?InformaticaorOracle?

WhichJOINsdatafaster?OracleorInformatica?

TestPreparation



5.SourcedatabasetableisnotavailableinOraclesharedpoolbeforethesameisread6.ThereisnosessionlevelpartitioninInformaticaPowerCentre7.ThereisnoparallelhintprovidedinextractionSQLquery8.InformaticaJOINERhasenoughcachesizeWehaveusedtwosetsofInformaticaPowerCentremappingscreatedinInformaticaPowerCentredesigner.Thefirstmappingm_db_side_joinwilluseanINNERJOINclauseinthesourcequalifiertosortdataindatabaselevel.Secondmappingm_Infa_side_joinwilluseanInformaticaJOINERtoJOINdataininformaticalevel.Wehaveexecutedthesemappingswithdifferentdatapointsandloggedtheresult.Furthertotheabovetestwewillexecutem_db_side_joinmappingonceagain,thistimewithproperdatabasesideindexesandstatisticsandlogtheresults.

ThefollowinggraphshowstheperformanceofInformaticaandDatabaseintermsoftimetakenbyeachsystemtosortdata.Theaveragetimeisplottedalongverticalaxisanddatapointsareplottedalonghorizontalaxis.

DataPoints MasterTableRecordCount DetailTableRecordCount

1 0.1M 1M

2 0.2M 2M

3 0.4M 4M

4 0.6M 6M

1.Averageserverloadremainssameduringalltheexperiments2.Averagenetworkspeedremainssameduringalltheexperiments

1.Thisdatacanonlybeusedforperformancecomparisonbutcannotbeusedforperformancebenchmarking.2.Thisdataisonlyindicativeandmayvaryindifferenttestingconditions.

Informaticaisoneoftheleadingdataintegrationtoolsintodaysworld.Morethan4,000enterprisesworldwiderelyonInformaticatoaccess,integrateandtrusttheirinformationassetswithit.Ontheotherhand,OracledatabaseisarguablythemostsuccessfulandpowerfulRDBMSsystemthatistrustedfrom1980sinallsortsofbusinessdomainandacrossallmajorplatforms.Bothofthesesystemsarebestsinthetechnologiesthattheysupport.Butwhenitcomestotheapplicationdevelopment,developersoftenfacechallengetostriketherightbalanceofoperationalloadsharingbetweenthesesystems.ThinkaboutatypicalETLoperationoftenusedinenterpriseleveldataintegration.AlotofdataprocessingcanbeeitherredirectedtothedatabaseortotheETLtool.Ingeneral,boththedatabaseandtheETLtoolarereasonablycapableofdoingsuchoperationswithalmostsameefficiencyandcapability.Butinordertoachievetheoptimized

Result

Verdict

Inourtestenvironment,Oracle10gperformsJOINoperation24%fasterthanInformaticaJoinerTransformationwhilewithoutIndexand42%fasterwithDatabaseIndex

Assumption

Note

Whichisthefastest?InformaticaorOracle?



performance,adevelopermustcarefullyconsideranddecidewhichsystems/heshouldbetrustingwithforeachindividualprocessingtask.Inthisarticle,wewilltakeabasicdatabaseoperationSorting,andwewillputthesetwosystemstotestinordertodeterminewhichdoesitfasterthantheother,ifatall.

Asanapplicationdeveloper,youhavethechoiceofeitherusingORDERBYindatabaseleveltosortyourdataorusingSORTERTRANSFORMATIONinInformaticatoachievethesameoutcome.Thequestioniswhichsystemperformsthisfaster?

Wewillperformthesametestwithdifferentdatapoints(datavolumes)andlogtheresults.Wewillstartwith1millionrecordsandwewillbedoublingthevolumeforeachnextdatapoints.Herearethedetailsofthesetupwewilluse,1.Oracle10gdatabaseasrelationalsourceandtarget2.InformaticaPowerCentre8.5asETLtool3.DatabaseandInformaticasetupondifferentphysicalserversusingHPUNIX4.Sourcedatabasetablehasnoconstraint,noindex,nodatabasestatisticsandnopartition5.SourcedatabasetableisnotavailableinOraclesharedpoolbeforethesameisread6.ThereisnosessionlevelpartitioninInformaticaPowerCentre7.ThereisnoparallelhintprovidedinextractionSQLquery8.Thesourcetablehas10columnsandfirst8columnswillbeusedforsorting9.InformaticasorterhasenoughcachesizeWehaveusedtwosetsofInformaticaPowerCentremappingscreatedinInformaticaPowerCentredesigner.Thefirstmappingm_db_side_sortwilluseanORDERBYclauseinthesourcequalifiertosortdataindatabaselevel.Secondmappingm_Infa_side_sortwilluseanInformaticasortertosortdataininformaticalevel.Wehaveexecutedthesemappingswithdifferentdatapointsandloggedtheresult.

ThefollowinggraphshowstheperformanceofInformaticaandDatabaseintermsoftimetakenbyeachsystemtosortdata.Thetimeisplottedalongverticalaxisanddatavolumeisplottedalonghorizontalaxis.

1.Averageserverloadremainssameduringalltheexperiments2.Averagenetworkspeedremainssameduringalltheexperiments

Thisdatacanonlybeusedforperformancecomparisonbutcannotbeusedforperformancebenchmarking.

Whichsortsdatafaster?OracleorInformatica?

TestPreparation

Result

Verdict

TheaboveexperimentdemonstratesthatOracledatabaseisfasterinSORToperationthanInformaticabyanaveragefactorof14%.Assumption

Note



SauravMitra

[http://www.dwbiconcepts.com/basicconcept/3etl/32informaticarejectorbadfiles.html?

tmpl=component&print=1&layout=default&page=] [http://cdn1.dwbiconcepts.com/basicconcept/3etl/32informaticarejectorbadfiles.pdf]inShare[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]00diggsdigg

.

[http://www.addthis.com/bookmark.php?v=250&username=xa4bc2f37319cd6ca8]Whenwerunasession,theintegrationservicemaycreatearejectfileforeachtargetinstanceinthemappingtostorethetargetrejectrecord.WiththehelpoftheSessionLogandRejectFilewecanidentifythecauseofdatarejectioninthesession.Eliminatingthecauseofrejectionwillleadtorejectionfreeloadsinthesubsequentsessionruns.IftheInformaticaWriterortheTargetDatabaserejectsdataduetoanyvalidreasontheintegrationservicelogstherejectedrecordsintotherejectfile.Everytimewerunthesessiontheintegrationserviceappendstherejectedrecordstotherejectfile.

BydefaulttheIntegrationservicecreatestherejectfilesorbadfilesinthe$PMBadFileDirprocessvariabledirectory.ItwritestheentirerejectrecordrowinthebadfilealthoughtheproblemmaybeinanyoneoftheColumns.Therejectfileshaveadefaultnamingconventionlike[target_instance_name].bad.Ifweopentherejectfileinaneditorwewillseecommaseparatedvalueshavingsometags/indicatorandsomedatavalues.WewillseetwotypesofIndicatorsintherejectfile.OneistheRowIndicatorandtheotheristheColumnIndicator.ForreadingthebadfilethebestmethodistocopythecontentsofthebadfileandsavingthesameasaCSV(CommaSepataredValue)file.Openingthecsvfilewillgiveanexcelsheettypelookandfeel.ThefirstmostcolumnintherejectfileistheRowIndicator,thatdetermineswhethertherowwasdestinedforinsert,update,deleteorreject.ItisbasicallyaflagthatdeterminestheUpdateStrategyforthedatarow.WhentheCommitTypeofthesessionisconfiguredasUserdefinedtherowindicatorindicateswhetherthetransactionwasrolledbackduetoanonfatalerror,orifthecommittedtransactionwasinafailedtargetconnectiongroup.

RowIndicator IndicatorSignificance RejectedBy

0 Insert Writerortarget

1 Update Writerortarget

2 Delete Writerortarget

3 Reject Writer

4 Rolledbackinsert Writer

5 Rolledbackupdate Writer

6 Rolledbackdelete Writer

7 Committedinsert Writer

8 Committedupdate Writer

9 Committeddelete Writer

NowcomestheColumnDatavaluesfollowedbytheirColumnIndicators,thatdeterminesthedataqualityofthecorrespondingColumn.

InformaticaRejectFileHowtoIdentifyrejectionreason[http://www.dwbiconcepts.com/basicconcept/3etl/32informaticarejectorbadfiles.html]

WorkingwithInformaticaBadFilesorRejectFiles

ListofValuesofRowIndicators:



>

ColumnIndicator

Typeofdata WriterTreatsAs

DValiddataorGoodData.

Writerpassesittothetargetdatabase.Thetargetacceptsitunlessadatabaseerroroccurs,suchasfindingaduplicatekeywhileinserting.

OOverflowedNumericData.

Numericdataexceededthespecifiedprecisionorscaleforthecolumn.Baddata,ifyouconfiguredthemappingtargettorejectoverflowortruncateddata.

N NullValue.Thecolumncontainsanullvalue.Gooddata.Writerpassesittothetarget,whichrejectsitifthetargetdatabasedoesnotacceptnullvalues.

TTruncatedStringData.

Stringdataexceededaspecifiedprecisionforthecolumn,sotheIntegrationServicetruncatedit.Baddata,ifyouconfiguredthemappingtargettorejectoverflowortruncateddata.

Alsotobenotedthatthesecondcolumncontainscolumnindicatorflagvalue'D'whichsignifiesthattheRowIndicatorisvalid.NowletusseehowDatainaBadFilelookslike:

0,D,7,D,John,D,5000.375,O,,N,BrickLandRoadSingapore,T

Usingincrementalaggregation,weapplycapturedchangesinthesourcedata(CDCpart)toaggregatecalculationsinasession.Ifthesourcechangesincrementallyandwecancapturethechanges,thenwecanconfigurethesessiontoprocessthosechanges.ThisallowstheIntegrationServicetoupdatethetargetincrementally,ratherthanforcingittodeletepreviousloadsdata,processtheentiresourcedataandrecalculatethesamedataeachtimeyourunthesession.

Whenthesessionrunswithincrementalaggregationenabledforthefirsttimesay1stweekofJan,wewillusetheentiresource.ThisallowstheIntegrationServicetoreadandstorethenecessaryaggregatedatainformation.On2ndweekofJan,whenwerunthesessionagain,wewillfilterouttheCDCrecordsfromthesourcei.etherecordsloadedaftertheinitialload.TheIntegrationServicethenprocessesthesenewdataandupdatesthetargetaccordingly.

Useincrementalaggregationwhenthechangesdonotsignificantlychangethetarget.Ifprocessingtheincrementallychangedsourcealtersmorethanhalftheexistingtarget,thesessionmaynotbenefitfromusingincrementalaggregation.Inthiscase,dropthetableandrecreatethetargetwithentiresourcedataandrecalculatethesameaggregationformula.INCREMENTALAGGREGATION,maybehelpfulincaseswhenweneedtoloaddatainmonthlyfactsinaweeklybasis.Letusseeasamplemappingtoimplementincrementalaggregation:

Image:IncrementalAggregationSampleMapping[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]LookattheSourceQualifierquerytofetchtheCDCpartusingaBATCH_LOAD_CONTROLtablethatsavesthelastsuccessfulloaddatefortheparticularmapping.Image:IncrementalAggregationSourceQualifier[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

LookattheportstabofExpressiontransformation.

ListofValuesofColumnIndicators:

ImplementingInformaticaIncrementalAggregation[http://www.dwbiconcepts.com/advance/4etl/26implementinginformaticasincrementalaggregation.html]

IncrementalAggregation



LookattheportstabofAggregatorTransformation.

NowthemostimportantsessionpropertiesconfiguationtoimplementincrementalAggregation



IfwewanttoreinitializetheaggregatecachesupposeduringfirstweekofeverymonthwewillconfigureanothersessionsameastheprevioussessiontheonlychangebeingtheReinitializeaggregatecachepropertycheckedin

Nowhavealookatthesourcetabledata:



CUSTOMER_KEY INVOICE_KEY AMOUNT LOAD_DATE

1111 5001 100 01/01/2010

2222 5002 250 01/01/2010

3333 5003 300 01/01/2010

1111 6007 200 07/01/2010

1111 6008 150 07/01/2010

2222 6009 250 07/01/2010

4444 1234 350 07/01/2010

5555 6157 500 07/01/2010

AfterthefirstLoadon1stweekofJan2010,thedatainthetargetisasfollows:

CUSTOMER_KEY INVOICE_KEY MON_KEY AMOUNT

1111 5001 201001 100

2222 5002 201001 250

3333 5003 201001 300

Nowduringthe2ndweekloaditwillprocessonlytheincrementaldatainthesourcei.ethoserecordshavingloaddategreaterthanthelastsessionrundate.Afterthe2ndweeksloadafterincrementalaggregationoftheincrementalsourcedatawiththeaggregatecachefiledatawillupdatethetargettablewiththefollowingdataset:

CUSTOMER_KEY INVOICE_KEY MON_KEY AMOUNT Remarks/Operation

1111 6008 201001 450 Thecachefileupdatedafteraggretation

2222 6009 201001 500 Thecachefileupdatedafteraggretation

3333 5003 201001 300 Thecachefileremainsthesameasbefore

4444 1234 201001 350 Newgrouprowinsertedincachefile

5555 6157 201001 500 Newgrouprowinsertedincachefile

Thefirsttimewerunanincrementalaggregationsession,theIntegrationServiceprocessestheentiresource.Attheendofthesession,theIntegrationServicestoresaggregatedataforthatsessionrunintwofiles,theindexfileandthedatafile.TheIntegrationServicecreatesthefilesinthecachedirectoryspecifiedintheAggregatortransformationproperties.Eachsubsequenttimewerunthesessionwithincrementalaggregation,weusetheincrementalsourcechangesinthesession.Foreachinputrecord,theIntegrationServicecheckshistoricalinformationintheindexfileforacorrespondinggroup.Ifitfindsacorrespondinggroup,theIntegrationServiceperformstheaggregateoperationincrementally,usingtheaggregatedataforthatgroup,andsavestheincrementalchange.Ifitdoesnotfindacorrespondinggroup,theIntegrationServicecreatesanewgroupandsavestherecorddata.

Whenwritingtothetarget,theIntegrationServiceappliesthechangestotheexistingtarget.Itsavesmodifiedaggregatedataintheindexanddatafilestobeusedashistoricaldatathenexttimeyourunthesession.Eachsubsequenttimewerunasessionwithincrementalaggregation,theIntegrationServicecreatesabackupoftheincrementalaggregationfiles.ThecachedirectoryfortheAggregatortransformationmustcontainenoughdiskspacefortwosetsofthefiles.

TheIntegrationServicecreatesnewaggregatedata,insteadofusinghistoricaldata,whenweconfigurethesessiontoreinitializetheaggregatecache,Deletecachefilesetc.WhentheIntegrationServicerebuildsincrementalaggregationfiles,thedatainthepreviousfilesislost.Note:Toprotecttheincrementalaggregationfilesfromfilecorruptionordiskfailure,periodicallybackupthefiles.

UsingInformaticaNormalizerTransformation[http://www.dwbiconcepts.com/basicconcept/3etl/23usinginformaticanormalizertransformation.html]



SauravMitra

[http://www.dwbiconcepts.com/basicconcept/3etl/23usinginformaticanormalizertransformation.html?

tmpl=component&print=1&layout=default&page=] [http://cdn1.dwbiconcepts.com/basicconcept/3etl/23usinginformaticanormalizertransformation.pdf]inShare[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]00diggsdigg

.Normalizer,anativetransformationinInformatica,caneasemanycomplexdatatransformationrequirement.Learnhowtoeffectivelyusenormalizerhere.

ANormalizerisanActivetransformationthatreturnsmultiplerowsfromasourcerow,itreturnsduplicatedataforsingleoccurringsourcecolumns.TheNormalizertransformationparsesmultipleoccurringcolumnsfromCOBOLsources,relationaltables,orothersources.Normalizercanbeusedtotransposethedataincolumnstorows.

NormalizereffectivelydoestheoppositeofwhatAggregatordoes!

Thinkofarelationaltablethatstoresfourquartersofsalesbystoreandweneedtocreatearowforeachsalesoccurrence.WecanconfigureaNormalizertransformationtoreturnaseparaterowforeachquarterlikebelow..Thefollowingsourcerowscontainfourquartersofsalesbystore:SourceTable

Store Quarter1 Quarter2 Quarter3 Quarter4

Store1 100 300 500 700

Store2 250 450 650 850

TheNormalizerreturnsarowforeachstoreandsalescombination.Italsoreturnsanindex(GCID)thatidentifiesthequarternumber:

TargetTable

Store Sales Quarter

Store1 100 1

Store1 300 2

Store1 500 3

Store1 700 4

Store2 250 1

Store2 450 2

Store2 650 3

Store2 850 4

Supposewehavethefollowingdatainsource:

Name Month Transportation HouseRent Food

Sam Jan 200 1500 500

John Jan 300 1200 300

Tom Jan 300 1350 350

Sam Feb 300 1550 450

John Feb 350 1200 290

Tom Feb 350 1400 350

UsingNoramalizerTransformation

ExampleofDataTransposeusingNormalizer

HowInformaticaNormalizerWorks



andweneedtotransformthesourcedataandpopulatethisasbelowinthetargettable:

Name Month ExpenseType Expense

Sam Jan Transport 200

Sam Jan Houserent 1500

Sam Jan Food 500

John Jan Transport 300

John Jan Houserent 1200

John Jan Food 300

Tom Jan Transport 300

Tom Jan Houserent 1350

Tom Jan Food 350

..likethis.NowbelowisthescreenshotofacompletemappingwhichshowshowtoachievethisresultusingInformatica

PowerCenterDesigner.Image:NormalizationMappingExample1[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

Iwillexplainthemappingfurtherbelow.

FirstweneedtosetthenumberofoccurencespropertyoftheExpenseheadas3intheNormalizertaboftheNormalizertransformation,sincewehaveFood,HouserentandTransportation.Whichinturnwillcreatethecorresponding3inputportsintheportstabalongwiththefieldsIndividualandMonth

InthePortstaboftheNormalizertheportswillbecreatedautomaticallyasconfiguredintheNormalizertab.Interestinglywewillobservetwonewcolumnsnamely,

GK_EXPENSEHEADGCID_EXPENSEHEAD

GKfieldgeneratessequencenumberstartingfromthevalueasdefinedinSequencefieldwhileGCIDholdsthevalueoftheoccurencefieldi.e.thecolumnnooftheinputExpensehead.

SettingUpNormalizerTransformationProperty



Here1isforFOOD,2isforHOUSERENTand3isforTRANSPORTATION.

NowtheGCIDwillgivewhichexpensecorrespondstowhichfieldwhileconvertingcolumnstorows.BelowisthescreenshotoftheexpressiontohandlethisGCIDefficiently:

Image:ExpressiontohandleGCID[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]

ALookUpcachedoesnotchangeoncebuilt.Butwhatiftheunderlyinglookuptablechangesthedataafterthelookupcacheiscreated?Isthereawaysothatthecachealwaysremainuptodateeveniftheunderlyingtablechanges?DynamicLookupCache

Let'sthinkaboutthisscenario.Youareloadingyourtargettablethroughamapping.InsidethemappingyouhaveaLookupandintheLookup,youareactuallylookingupthesametargettableyouareloading.Youmayaskme,"So?What'sthebigdeal?Wealldoitquiteoften...".Andyesyouareright.Thereisno"bigdeal"becauseInformatica(generally)cachesthelookuptableintheverybeginningofthemapping,sowhatever

recordgettinginsertedtothetargettablethroughthemapping,willhavenoeffectontheLookupcache.Thelookupwillstillholdthepreviouslycacheddata,eveniftheunderlyingtargettableischanging.ButwhatifyouwantyourLookupcachetogetupdatedasandwhenthetargettableischanging?Whatifyouwantyourlookupcachetoalwaysshowtheexactsnapshotofthedatainyourtargettableatthatpointintime?Clearlythisrequirementwillnotbefullfilledincaseyouuseastaticcache.Youwillneedadynamiccachetohandlethis.

Tounderstandthis,let'sfirstunderstandastaticcachescenario.

SauravMitra

[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?

tmpl=component&print=1&layout=default&page=] [http://cdn1.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.pdf]

ArticleIndexInformaticaDynamicLookupCache[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html]WhatisStaticCache[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=1]WhatisDynamicCache[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=2]Howdoesdynamiccachework[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=3]DynamicLookupMappingExample[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=4]DynamicLookupSequenceID[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=5]DynamicLookupPorts[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=6]

InformaticaDynamicLookupCache[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html]

Butwhyanyonewillneedadynamiccache?

InformaticaDynamicLookupCache[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html]



NULLhandlinginLookUp[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=7]OtherDetails[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?start=8]AllPages[http://www.dwbiconcepts.com/basicconcept/3etl/22dynamiclookupcache.html?showall=1]Page1of9inShare[file:///E:/Tutorial/fundooo%20informatica%20(1).doc]00diggsdigg

.ALookUpcachedoesnotchangeoncebuilt.Butwhatiftheunderlyinglookuptablechangesthedataafterthelookupcacheiscreated?Isthereawaysothatthecachealwaysremainuptodateeveniftheunderlyingtablechanges?DynamicLookupCache

Let'sthinkaboutthisscenario.Youareloadingyourtargettablethroughamapping.InsidethemappingyouhaveaLookupandintheLookup,youareactuallylookingupthesametargettableyouareloading.Youmayaskme,"So?What'sthebigdeal?Wealldoitquiteoften...".Andyesyouareright.Thereisno"bigdeal"becauseInformatica(generally)cachesthelookuptableintheverybeginningofthemapping,sowhatever

recordgettinginsertedtothetargettablethroughthemapping,willhavenoeffectontheLookupcache.Thelookupwillstillholdthepreviouslycacheddata,eveniftheunderlyingtargettableischanging.ButwhatifyouwantyourLookupcachetogetupdatedasandwhenthetargettableischanging?Whatifyouwantyourlookupcachetoalwaysshowtheexactsnapshotofthedatainyourtargettableatthatpointintime?Clearlythisrequirementwillnotbefullfilledincaseyouuseastaticcache.Youwillneedadynamiccachetohandlethis.

Tounderstandthis,let'sfirstunderstandastaticcachescenario.

Let'ssupposeyourunaretailbusinessandmaintainallyourcustomerinformationinacustomermastertable(RDBMStable).Everynight,allthecustomersfromyourcustomermastertableisloadedintoaCustomerDimensiontableinyourdatawarehouse.Yoursourcecustomertableisatransactionsystemtable,probablyin3rdnormalform,anddoesnotstorehistory.Meaning,ifacustomerchangeshisaddress,theoldaddressisupdatedwiththenewaddress.Butyourdatawarehousetablestoresthehistory(maybeintheformofSCDTypeII).Thereisamapthatloadsyourdatawarehousetablefromthesourcetable.TypicallyyoudoaLookupontarget(staticcache)andcheckwithyoureveryincomingcustomerrecordtodetermineifthecustomerisalreadyexistingintargetornot.Ifthecustomerisnotalreadyexistingintarget,youconcludethecustomerisnewandINSERTtherecordwhereasifthecustomerisalreadyexisting,youmaywanttoupdatethetargetrecordwiththisnewrecord(iftherecordisupdated).Thisisillustratedbelow,Youdon'tneeddynamicLookupcacheforthis

Image:AstaticLookupCachetodetermineifasourcerecordisneworupdatable

NoticeinthepreviousexampleImentionedthatyoursourcetableisanRDBMStable.Thisensuresthatyoursourcetabledoesnothaveanyduplicaterecord.But,Whatifyouhadaflatfileassourcewithmanyduplicaterecords?Wouldthescenariobesame?No,seethebelowillustration.

Butwhyanyonewillneedadynamiccache?

StaticCacheScenario

DynamicLookupCacheScenario



Image:AScenarioillustratingtheuseofdynamiclookupcacheHerearesomemoreexampleswhenyoumayconsiderusingdynamiclookup,

UpdatingamastercustomertablewithbothnewandupdatedcustomerinformationcomingtogetherasshownaboveLoadingdataintoaslowlychangingdimensiontableandafacttableatthesametime.Remember,youtypicallylookupthedimensionwhileloadingtofact.Soyouloaddimensiontablebeforeloadingfacttable.Butusingdynamiclookup,youcanloadbothsimultaneously.Loadingdatafromafilewithmanyduplicaterecordsandtoeliminateduplicaterecordsintargetbyupdatingaduplicaterowi.e.keepingthemostrecentrowortheinitialrowLoadingthesamedatafrommultiplesourcesusingasinglemapping.JustconsiderthepreviousRetailbusinessexample.IfyouhavemorethanoneshopsandLindahasvisitedtwoofyourshopsforthefirsttime,customerrecordLindawillcometwiceduringthesameload.

WhentheIntegrationServicereadsarowfromthesource,itupdatesthelookupcachebyperformingoneofthefollowingactions:

Insertstherowintothecache:Iftheincomingrowisnotinthecache,theIntegrationServiceinsertstherowinthecachebasedoninputportsorgeneratedSequenceID.TheIntegrationServiceflagstherowasinsert.Updatestherowinthecache:Iftherowexistsinthecache,theIntegrationServiceupdatestherowinthecachebasedontheinputports.TheIntegrationServiceflagstherowasupdate.Makesnochangetothecache:ThishappenswhentherowexistsinthecacheandthelookupisconfiguredorspecifiedToInsertNewRowsonlyor,therowisnotinthecacheandlookupisconfiguredtoupdateexistingrowsonlyor,therowisinthecache,butbasedonthelookupcondition,nothingchanges.TheIntegrationServiceflagstherowasunchanged.

NoticethatIntegrationServiceactuallyflagstherowsbasedontheabovethreeconditions.Andthat'sagreatthing,because,ifyouknowtheflagyoucanactuallyreroutetherowtoachievedifferentlogic.Thisflagportiscalled

NewLookupRow

Usingthevalueofthisport,therowscanberoutedforinsert,updateortodonothing.YoujustneedtouseaRouterorFiltertransformationfollowedbyanUpdateStrategy.Oh,forgottotellyoutheactualvaluesthatyoucanexpectinNewLookupRowportare:

0=IntegrationServicedoesnotupdateorinserttherowinthecache.1=IntegrationServiceinsertstherowintothecache.2=IntegrationServiceupdatestherowinthecache.

WhentheIntegrationServicereadsarow,itchangesthelookupcachedependingontheresultsofthelookupqueryandtheLookuptransformationpropertiesyoudefine.Itassignsthevalue0,1,or2totheNewLookupRowporttoindicateifitinsertsorupdatestherowinthecache,ormakesnochange.

So,Howdoesdynamiclookupwork?



Posted2ndJune2012byShankarPrasad

0 Addacomment

2ndJune2012

*******************ShankarPrasad*******************************

1.Can2FactTablessharesamedimensionsTables?HowmanyDimensiontablesareassociatedwithoneFactTableurproject?Ans:Yes

2.WhatisROLAP,MOLAP,andDOLAP...?Ans:ROLAP(RelationalOLAP),MOLAP(MultidimensionalOLAP),andDOLAP(DesktopOLAP).InthesethreeOLAParchitectures,theinterfacetotheanalyticlayeristypicallythesamewhatisquitedifferentishowthedataisphysicallystored. InMOLAP, thepremise is thatonlineanalyticalprocessing isbest implementedbystoringthedatamultidimensionallythatis,datamustbestoredmultidimensionallyinordertobeviewedinamultidimensionalmanner.InROLAP,architectsbelievetostorethedataintherelationalmodelforinstance,OLAPcapabilitiesarebestprovidedagainsttherelationaldatabase.DOLAP, isavariationthatexiststoprovideportabilityfortheOLAPuser.Itcreatesmultidimensionaldatasetsthatcanbetransferredfromservertodesktop,requiringonlytheDOLAPsoftwaretoexistonthetargetsystem.Thisprovidessignificantadvantagestoportablecomputerusers,suchassalespeoplewhoarefrequentlyontheroadanddonothavedirectaccesstotheirofficeserver.

3.WhatisanMDDB?andWhatisthedifferencebetweenMDDBsandRDBMSs?Ans: Multidimensional Database There are two primary technologies that are used for storing the datausedinOLAPapplications.Thesetwotechnologiesaremultidimensionaldatabases(MDDB)andrelationaldatabases(RDBMS).Themajordifference betweenMDDBsandRDBMSsis inhowtheystoredata.Relationaldatabasesstore theirdata inaseriesoftablesand columns. Multidimensional databases, on the other hand, store their data in a largemultidimensionalarrays. Forexample, inanMDDBworld,youmightrefertoasalesfigureasSaleswithDate,Product,andLocationcoordinatesof1212001,Car,andsouth,respectively.AdvantagesofMDDB:Retrievalisveryfastbecause

ThedatacorrespondingtoanycombinationofdimensionmemberscanberetrievedwithasingleI/O.Dataisclusteredcompactlyinamultidimensionalarray.Valuesarecaluculatedaheadoftime.Theindexissmallandcanthereforeusuallyresidecompletelyinmemory.

StorageisveryefficientbecauseTheblockscontainonlydata.Asingleindexlocatestheblockcorrespondingtoacombinationofsparsedimensionnumbers.

4.WhatisMDBmodelingandRDBModeling?Ans:

5.WhatisMappletandhowdoucreateMapplet?Ans: A mapplet is a reusable object that represents a set of transformations. It allows you to reusetransformationlogicandcancontainasmanytransformationsasyouneed.Createamappletwhenyouwanttouseastandardizedsetoftransformationlogicinseveralmappings.Forexample,ifyouhaveaseveralfacttablesthatrequireaseriesofdimensionkeys,youcancreateamappletcontaining

DatawarehouseandInformaticaInterviewQuestion

DatawarehouseandInformaticaInterviewQuestion



aseriesofLookuptransformationstofindeachdimensionkey.Youcanthenusethemappletineachfacttablemapping,ratherthanrecreatethesamelookuplogicineachmapping.Tocreateanewmapplet:1.IntheMappletDesigner,chooseMappletsCreateMapplet.2.Enteradescriptivemappletname.TherecommendednamingconventionformappletsismpltMappletName.3.ClickOK.TheMappingDesignercreatesanewmappletintheMappletDesigner.4.ChooseRepositorySave.

6.Whatforisthetransformationsareused?Ans:Transformationsarethemanipulationofdatafromhowitappearsinthesourcesystem(s)intoanotherforminthedata warehouseormart inawaythatenhancesorsimplifies itsmeaning.Inshort,utransformdata intoinformation.ThisincludesDatamerging,Cleansing,Aggregation:Datamerging:Processofstandardizingdatatypesandfields.Supposeonesourcesystemcallsintegertypedataassmallint where as another calls similar data as decimal. The data from the two source systems needs torationalizedwhenmovedintotheoracledataformatcallednumber.Cleansing:Thisinvolvesidentifyinganychanginginconsistenciesorinaccuracies.

Eliminatinginconsistenciesinthedatafrommultiplesources.Convertingdatafromdifferentsystemsintosingleconsistentdatasetsuitableforanalysis.Meetsastandardforestablishingdataelements,codes,domains,formatsandnamingconventions.Correctdataerrorsandfillsinformissingdatavalues.Aggregation:Theprocesswherebymultipledetailedvaluesarecombined intoasinglesummaryvaluetypicallysummationnumbersrepresentingdollarsspendorunitssold.Generatesummarizeddataforuseinaggregatefactanddimensiontables.

Data Transformation is an interesting concept in that some transformation can occur during theextract,someduringthe transformation,orevenin limitedcasesduringloadportionoftheETLprocess.Thetypeoftransformationfunctionu needwillmostoftendeterminewhere it shouldbeperformed.Some transformation functionscouldevenbeperformedinmorethanoneplace.Bzemanyofthetransformationsuwillwanttoperformalreadyexistinsomeformoranotherinmorethanoneofthethreeenvironments(sourcedatabaseorapplication,ETLtool,orthetargetdb).7.WhatisthedifferencebtweenOLTP&OLAP?Ans:OLTPstandforOnlineTransactionProcessing.This isstandard,normalizeddatabasestructure.OLTPisdesignedfor

Transactions, which means that inserts, updates, and deletes must be fast. Imagine a call center thattakesorders.Calltakersarecontinuallytakingcallsandenteringordersthatmaycontainnumerousitems.Eachorderandeachitemmustbeinsertedintoadatabase.Sincetheperformanceofdatabaseiscritical,wewant tomaximize thespeedof inserts (andupdatesanddeletes).Tomaximizeperformance,wetypicallytrytoholdasfewrecordsinthedatabaseaspossible.

OLAPstands forOnlineAnalytical Processing.OLAP is a term thatmeansmany things tomanypeople.Here,wewillusethetermOLAPandStarSchemaprettymuchinterchangeably.Wewillassumethatstarschemadatabase is anOLAP system.( This is not the same thing thatMicrosoft calls OLAP theyextendOLAPtomeanthecubestructuresbuiltusingtheirproduct,OLAPServices).Here,wewillassumethatanysystemofreadonly,historical,aggregateddataisanOLAPsystem.

Adatawarehouse(ormart)iswayofstoringdataforlaterretrieval.Thisretrievalisalmostalwaysusedtosupportdecisionmaking in theorganization.That iswhymanydatawarehousesareconsidered tobeDSS(DecisionSupportSystems).

Bothadatawarehouseandadatamartarestoragemechanismsforreadonly,historical,aggregateddata.Byreadonly,wemeanthattheperson lookingatthedatawontbechanging it. Ifauserwantsatthesalesyesterdayforacertainproduct,theyshouldnothavetheabilitytochangethatnumber.

Thehistoricalpartmayjustbeafewminutesold,butusuallyitisatleastadayold.Adatawarehouseusuallyholdsdatathatgoesbackacertainperiodintime,suchasfiveyears.Incontrast,standardOLTPsystemsusuallyonlyholddataaslongasitiscurrentoractive.Anordertable,forexample,maymoveorderstoanarchivetableoncetheyhavebeencompleted,shipped,andreceivedbythecustomer.

Whenwesaythatdatawarehousesanddatamartsholdaggregateddata,weneedtostressthattherearemanylevelsofaggregationinatypicaldatawarehouse.

8.IfdatasourceisintheformofExcelSpreadsheetthenhowdouse?



Ans:PowerMartandPowerCentertreataMicrosoftExcelsourceasarelationaldatabase,notaflatfile.Likerelationalsources,theDesignerusesODBCtoimportaMicrosoftExcelsource.YoudonotneeddatabasepermissionstoimportMicrosoftExcelsources.ToimportanExcelsourcedefinition,youneedtocompletethefollowingtasks:

InstalltheMicrosoftExcelODBCdriveronyoursystem.CreateaMicrosoftExcelODBCdatasourceforeachsourcefileintheODBC32bitAdministrator.PrepareMicrosoftExcelspreadsheetsbydefiningrangesandformattingcolumnsofnumericdata.ImportthesourcedefinitionsintheDesigner.

Onceyoudefinerangesandformatcells,youcanimporttherangesintheDesigner.Rangesdisplayassourcedefinitionswhenyouimportthesource.

9.WhichdbisRDBMSandwhichisMDDBcanunamethem?Ans:MDDBex.OracleExpressServer(OES),EssbasebyHyperionSoftware,PowerplaybyCognosandRDBMSex.Oracle,SQLServeretc.

10.Whatarethemodules/toolsinBusinessObjects?Explaintheierpurposebriefly?Ans: BO Designer, Business Query for Excel,BOReporter, Infoview,Explorer,WEBI, BO Publisher, andBroadcastAgent,BOZABO).InfoView:ITportalentryintoWebIntelligence&BusinessObjects.Basemodulerequiredforalloptionstoviewandrefreshreports.Reporter:Upgradetocreate/modifyreportsonLANorWeb.Explorer:UpgradetoperformOLAPprocessingonLANorWeb.Designer:Createssemanticlayerbetweenuseranddatabase.Supervisor:Administerandcontrolaccessforgroupofusers.WebIntelligence:Integratedquery,reporting,andOLAPanalysisovertheWeb. Broadcast Agent: Used to schedule, run, publish, push, and broadcast prebuilt reports andspreadsheets,includingevent notificationandresponsecapabilities,eventfiltering,andcalendarbasednotification,overtheLAN,e mail, pager,Fax, Personal Digital Assistant( PDA), ShortMessagingService(SMS),etc. Set Analyzer Applies setbased analysis to perform functions such as execlusion, intersections,unions,andoverlapsvisually.DeveloperSuiteBuildpackaged,analytical,orcustomizedapps.

11.WhataretheAdhocquries,CannedQuries/Reports?andHowdoucreatethem?(PlzcheckthispageC\:BObjects\Quries\DataWarehouseAboutQueries.htm)Ans:Thedatawarehousewillcontaintwotypesofquery.Therewillbefixedqueriesthatareclearlydefined

and well understood, such as regular reports, canned queries (standard reports) and commonaggregations.Therewillalsobeadhocqueriesthatareunpredictable,bothinquantityandfrequency.

Ad Hoc Query: Ad hoc queries are the starting point for any analysis into a database. Any businessanalyst wants to know what is inside the database. He then proceeds by calculating totals, averages,maximumandminimumvaluesformostattributeswithinthedatabase.Theseareunpredictableelementof a data warehouse. It is exactly that ability to run any query when desired and expect a reasonableresponsethatmakesthedatawarhouseworthwhile,andmakesthedesignsuchasignificantchallenge.The enduser access tools are capable of automatically generating the databasequery that answers anyQuestionposedbytheuser.Theuserwilltypicallyposequestionsintermsthattheyarefamilierwith(forexample,salesbystorelastweek)thisisconvertedintothedatabasequerybytheaccesstool,whichisawareofthestructureofinformationwithinthedatawarehouse.Canned queries: Canned queries are predefined queries. In most instances, canned queries containpromptsthatallowyoutocustomizethequeryforyourspecificneeds.Forexample,apromptmayaskyou for a School, department, term, or section ID. In this instance you would enter the name of theSchool, department or term, and thequerywill retrieve the specifieddata from theWarehouse.You canmeasureresourcerequirementsofthesequeries,andtheresultscanbeusedforcapacitypalnningandfordatabasedesign.Themainreasonforusingacannedqueryorreportratherthancreatingyourownisthatyourchancesofmisinterpretingdataorgetting thewronganswerare reduced.Youareassuredofgetting the rightdataandtherightanswer.

12.HowmanyFacttablesandhowmanydimensiontablesudid?Whichtableprecedeswhat?Ans:http://www.ciobriefings.com/whitepapers/StarSchema.asp

13.WhatisthedifferencebetweenSTARSCHEMA&SNOWFLAKESCHEMA?Ans:http://www.ciobriefings.com/whitepapers/StarSchema.asp

14.WhydiduchooseSTARSCHEMAonly?WhatarethebenefitsofSTARSCHEMA?Ans: Because its denormalized structure , i.e., Dimension Tables are denormalized. Why to denormalizemeansthefirst(andoftenonly)answeris:speed.OLTPstructureisdesignedfordatainserts,updates,anddeletes,butnotdataretrieval.Therefore,



wecanoftensqueezesomespeedoutofitbydenormalizingsomeofthetablesandhavingqueriesgoagainstfewertables. Thesequeriesarefasterbecausetheyperformfewerjoinstoretrievethesamerecordset.JoinsarealsoconfusingtomanyEndusers.Bydenormalizing,wecanpresenttheuserwithaviewofthedatathatisfareasierforthemtounderstand.BenefitsofSTARSCHEMA:

FarfewerTables.Designedforanalysisacrosstime.Simplifiesjoins.Lessdatabasespace.Supportsdrillinginreports.Flexibilitytomeetbusinessandtechnicalneeds.

15.HowdouloadthedatausingInformatica?Ans:Usingsession.

16.(i)WhatisFTP?(ii)Howdouconnecttoremote?(iii)IsthereanotherwaytouseFTPwithoutaspecialutility?Ans: (i):TheFTP (File Transfer Protocol) utility program is commonly used for copying files to and fromothercomputers.These computersmay be at the same site or at different sites thousands ofmiles apart. FTP is generalprotocolthatworksonUNIXsystemsaswellasothernonUNIXsystems.

(ii):Remoteconnectcommands:ftpmachinenameex:ftp129.82.45.181[ftp://ftp%20129.82.45.181/]orftpiesg If the remotemachinehasbeen reachedsuccessfully,FTP respondsbyasking fora loginnameandpassword.Whenuenterurownloginnameandpasswordfortheremotemachine,itreturnsthepromptlikebelowftp> andpermitsuaccess tourownhomedirectoryon the remotemachine.Ushouldbeable tomovearoundinurowndirectoryandtocopyfilestoandfromurlocalmachineusingtheFTPinterfacecommands.Note:UcansetthemodeoffiletransfertoASCII(defaultandtransmitssevenbitspercharacter).UsetheASCIImodewithanyofthefollowing:RawData(e.g.*.dator*.txt,codebooks,orotherplaintextdocuments)SPSSPortablefiles.HTMLfiles.IfusetmodeoffiletransfertoBinary(thebinarymodetransmitsalleightbitsperbyteandthusprovideslesschanceofatransmissionerrorandmustbeusedtotransmitfilesotherthanASCIIfiles).Forexampleusebinarymodeforthefollowingtypesoffiles:

SPSSSystemfilesSASDatasetGraphicfiles(eg.,*.gif,*.jpg,*.bmp,etc.)MicrosoftOfficedocuments(*.doc,*.xls,etc.)

(iii):Yes.IfurusingWindows,ucanaccessatextbasedFTPutilityfromaDOSprompt.Todothis,performthefollowingsteps:

1.FromtheStartProgramsMSDosPrompt2.Enterftpftp.geocities.com[ftp://ftp.geocities.com/].Apromptwillappear(or)Enterftptogetftppromptftp>openhostnameex.ftp>openftp.geocities.com(Itconnecttothespecifiedhost).3.Enteruryahoo!GeoCitiesmembername.4.enteryouryahoo!GeoCitiespwd.YoucannowusestandardFTPcommandstomanagethefilesinyourYahoo!GeoCitiesdirectory.

17.WhatcmdisusedtotransfermultiplefilesatatimeusingFTP?Ans:mget==>Tocopymultiplefilesfromtheremotemachinetothelocalmachine.Youwillbepromptedforay/nanswerbeforetransferringeachfilemget*(copiesallfilesinthecurrentremotedirectorytourcurrentlocaldirectory,usingthesamefilenames).mput==>Tocopymultiplefilesfromthelocalmachinetotheremotemachine.18.WhatisanFilterTransformation?orwhatoptionsuhaveinFilterTransformation?Ans:TheFiltertransformationprovidesthemeansforfilteringrecordsinamapping.YoupassalltherowsfromasourcetransformationthroughtheFiltertransformation,thenenterafilterconditionforthetransformation.AllportsinaFilter



transformationareinput/output,andonlyrecordsthatmeettheconditionpassthroughtheFiltertransformation.

Youcannotconcatenateports frommore thanone transformation into theFilter transformation theinputportsforthefiltermustcomefromasingletransformation.Filtertransformationsexistwithintheflowofthemappingandcannotbeunconnected.TheFiltertransformationdoesnotallowsettingoutputdefaultvalues.

19.WhataredefaultsourceswhichwillsupportedbyInformaticaPowermart?Ans:

Relationaltables,views,andsynonyms.

Fixedwidthanddelimitedflatfilesthatdonotcontainbinarydata.COBOLfiles.

20.WhendoucreatetheSourceDefinition?CanIusethisSourceDefntoanyTransformation?Ans:When workingwith a file that contains fixedwidth binary data, youmust create the sourcedefinition.TheDesignerdisplaysthesourcedefinitionasatable,consistingofnames,datatypes,andconstraints.Touseasourcedefinitioninamapping,connectasourcedefinitiontoaSourceQualifierorNormalizertransformation.TheInformaticaServerusesthesetransformationstoreadthesourcedata.

21.WhatisActive&PassiveTransformation?Ans:ActiveandPassiveTransformations Transformations can be active or passive. Anactive transformation can change the number ofrecordspassedthroughit.A passive transformation never changes the record count.Forexample, the Filter transformationremovesrowsthatdonotmeetthefilterconditiondefinedinthetransformation.Activetransformationsthatmightchangetherecordcountincludethefollowing:

AdvancedExternalProcedureAggregatorFilterJoinerNormalizerRankSourceQualifier

Note: If you use PowerConnect to access ERP sources, the ERP SourceQualifier is also an activetransformation./* Youcan connectonlyoneof theseactive transformations to the same transformationortarget,sincetheInformaticaServercannotdeterminehowtoconcatenatedatafromdifferentsetsofrecordswithdifferentnumbersofrows.*/Passivetransformationsthatneverchangetherecordcountincludethefollowing:

LookupExpressionExternalProcedureSequenceGeneratorStoredProcedureUpdateStrategy

You can connect any number of these passive transformations, or connect one active

Note:Discardedrowsdonotappearinthesessionlogorrejectfiles

Tomaximizesessionperformance,includetheFiltertransformationasclosetothesourcesinthe

mappingaspossible.

Ratherthanpassingrecordsyouplantodiscardthroughthemapping,youthenfilteroutunwanteddata

earlyinthe

flowofdatafromsourcestotargets.



transformationwithanynumberofpassivetransformations,tothesametransformationortarget.

22.WhatisstagingAreaandWorkArea?Ans:StagingArea:HoldingTablesonDWServer.LoadedfromExtractProcessInputforIntegration/TransformationMayfunctionasWorkAreasOutputtoaworkareaorFactTable

TemporaryTablesMemory

23.WhatisMetadata?(plzreferDATAWHINGINTHEREALWORLDBOOKpage#125)Ans:Defn:DataAboutDataMetadatacontainsdescriptivedataforendusers.Inadatawarehousethetermmetadataisusedinanumberofdifferentsituations.

Metadataisusedfor:DatatransformationandloadDatamanagementQuerymanagement

Datatransformationandload:Metadatamaybeusedduringdata transformationand loadtodescribe thesourcedataandanychangesthat need to bemade. The advantage of storingmetadata about the data being transformed is that assource data changes the changes can be captured in the metadata, and transformation programsautomaticallyregenerated.Foreachsourcedatafieldthefollowinginformationisreqd:SourceField:

Uniqueidentifier(toavoidanyconfusionoccurringbetn2fieldsofthesameanmefromdifferentsources).

Name(Localfieldname).Type(storagetypeofdata,likecharacter,integer,floatingpointandsoon).Location

system(systemitcomesfromex.Accoutingsystem).object(objectthatcontainsitex.AccountTable).

Thedestinationfieldneedstobedescribedinasimilarwaytothesource:Destination:

UniqueidentifierNameType(databasedatatype,suchasChar,Varchar,Numberandsoon).Tablename(Nameofthetablethfieldwillbepartof).

Theotherinformationthatneedstobestoredisthetransformationortransformationsthatneedtobeappliedtoturnthesourcedataintothedestinationdata:Transformation:

Transformation(s)Name

Language(nameofthelanjuagethattransformationiswrittenin).modulename

syntaxTheNameistheuniqueidentifierthatdifferentiatesthisfromanyothersimilartransformations.

TheLanguageattributecontainsthenameofthelnguagethatthetransformationiswrittenin.Theother attributes aremodulenameandsyntax. Generally thesewill bemutually exclusive,withonlyonebeingdefined.ForsimpletransformationssuchassimpleSQLfunctionsthesyntaxwillbestored. For complex transformations the name of the module that contains the code is storedinstead.Datamanagement:

Metadataisreqdtodescribethedataasitresidesinthedatawarehouse.Thisisneededbythewarhousemanagertoallowittotrackandcontrolalldatamovements.Everyobjectinthedatabaseneedstobedescribed.

Metadataisneededforallthefollowing:Tables

Columnsname

typeIndexes

WorkArea:



Columnsname

typeViews

Columnsname

typeConstraints

nametypetable

columnsAggregations,PartitioninformationalsoneedtobestoredinMetadata(fordetailsreferpage#30)

QueryGeneration:Metadataisalsorequiredbythequerymangertoenableittogeneratequeries.ThesamemetadatacanbeusedbytheWhousemanagertodescribethedatainthedatawarehouseisalsoreqdbythequerymanager.

Thequerymangaerwillalsogeneratemetadataaboutthequeriesithasrun.Thismetadatacanbeusedtobuildahistoryofallquries runandgenerateaqueryprofile foreachuser,groupofusersand thedatawarehouseasawhole.

Themetadatathatisreqdforeachqueryis:querytablesaccessedcolumnsaccessedname

refenceidentifierrestrictionsappliedcolumnnametablenamereferenceidentifierrestrictionjoinCriteriaappliedaggregatefunctionsused group bycriteria sortcriteria

syntaxexecutionplan

resources

24.WhatkindofUnixflavouresurexperienced?

Ans:Solaris2.5SunOs5.5(OperatingSystem)

Solaris2.6SunOs5.6(OperatingSystem)

Solaris2.8SunOs5.8(OperatingSystem)

AIX4.0.3

5.5.12.5.1May96sun4c,sun4m,sun4d,sun4u,x86,ppc

5.62.6Aug.97sun4c,sun4m,sun4d,sun4u,x86

5.77Oct.98sun4c,sun4m,sun4d,sun4u,x86

5.882000sun4m,sun4d,sun4u,x86

25.WhatarethetasksthataredonebyInformaticaServer?Ans:TheInformaticaServerperformsthefollowingtasks:

ManagestheschedulingandexecutionofsessionsandbatchesExecutessessionsandbatchesVerifiespermissionsandprivilegesInteractswiththeServerManagerandpmcmd.



TheInformaticaServermovesdatafromsourcestotargetsbasedonmetadatastoredinarepository.Forinstructionsonhowtomoveandtransformdata,theInformaticaServerreadsamapping(atypeofmetadatathatincludestransformationsandsourceandtargetdefinitions).Eachmappingusesasessiontodefineadditionalinformationandtooptionallyoverridemappingleveloptions.Youcangroupmultiplesessionstorunasasingleunit,knownasabatch.

26.WhatarethetwoprogramsthatcommunicatewiththeInformaticaServer?Ans: Informatica provides Server Manager and pmcmd programs to communicate with the InformaticaServer:

ServerManager. A client applicationused to create andmanage sessions andbatches, and tomonitorand stop the Informatica Server. You can use information provided through the Server Manager totroubleshootsessionsandimprovesessionperformance.pmcmd. A commandline program that allows you to start and stop sessions and batches, stop theInformaticaServer,andverifyiftheInformaticaServerisrunning.

27.WhendoureinitializeAggregateCache?Ans:Reinitializing theaggregate cacheoverwriteshistorical aggregatedatawithnewaggregatedata.Whenyoureinitializetheaggregatecache,insteadofusingthecapturedchangesinsourcetables,youtypicallyneedtousetheusetheentiresourcetable. For example, you can reinitialize the aggregate cache if the source for a session changesincrementallyeverydayandcompletelychangesonceamonth.Whenyoureceivethenewmonthlysource,youmightconfigurethesessiontoreinitializetheaggregatecache,truncatetheexistingtarget,andusethenewsourcetableduringthesession.

Toreinitializetheaggregatecache:1.IntheServerManager,openthesessionpropertysheet.2.ClicktheTransformationstab.3.CheckReinitializeAggregateCache.4.ClickOKthreetimestosaveyourchanges.5.Runthesession.

TheInformaticaServercreatesanewaggregatecache,overwritingtheexistingaggregatecache./?Tobecheckforstep6&step7aftersuccessfulrunofsession?/

6.Afterrunningthesession,openthepropertysheetagain.7.ClicktheDatatab.8.ClearReinitializeAggregateCache.9.ClickOK.

28.(i)WhatisTargetLoadOrderinDesigner?Ans:TargetLoadOrder:IntheDesigner,youcansettheorderinwhichtheInformaticaServersendsrecordstovarioustargetdefinitionsinamapping.Thisfeatureiscrucialifyouwanttomaintainreferentialintegritywheninserting,deleting,orupdatingrecordsintablesthathavetheprimarykeyandforeignkeyconstraintsappliedtothem.TheInformaticaServerwritesdatatoallthetargetsconnectedtothesameSourceQualifierorNormalizersimultaneously,tomaximizeperformance.

28.(ii)WhataretheminimimconditionthatuneedtohavesoastouseTargteLoadOrderOptioninDesigner?Ans:UneedtohaveMultipleSourceQualifiertransformations.TospecifytheorderinwhichtheInformaticaServersendsdatatotargets,createoneSourceQualifierorNormalizertransformationforeachtargetwithinamapping.Tosetthetargetloadorder,youthendeterminetheorderinwhicheachSourceQualifiersendsdatatoconnectedtargetsinthemapping.WhenamappingincludesaJoinertransformation,theInformaticaServersendsallrecordstotargetsconnectedtothatJoineratthesametime,regardlessofthetargetloadorder.

28(iii).HowdousettheTargetloadorder?Ans:Tosetthetargetloadorder:1.CreateamappingthatcontainsmultipleSourceQualifiertransformations.2.Afteryoucompletethemapping,chooseMappingsTargetLoadPlan. Adialogbox listsallSourceQualifiertransformations inthemapping,aswellasthetargetsthatreceivedatafromeachSourceQualifier.3.SelectaSourceQualifierfromthelist.

/?Note:Tobeclarifiedwhenservermangerworksforfollowing?/



4.ClicktheUpandDownbuttonstomovetheSourceQualifierwithintheloadorder.5.Repeatsteps3and4foranyotherSourceQualifiersyouwishtoreorder.6.ClickOKandChooseRepositorySave.

29.WhatucandowithRepositoryManager?Ans:WecandofollowingtasksusingRepositoryManager:Tocreateusernames,youmusthaveoneofthefollowingsetsofprivileges:AdministerRepositoryprivilege

SuperUserprivilegeTocreateausergroup,youmusthaveoneofthefollowingprivileges:AdministerRepositoryprivilege

SuperUserprivilegeToassignorrevokeprivileges,umusthvoneofthefollowingprivilege..

AdministerRepositoryprivilegeSuperUserprivilege

Note:Youcannotchangetheprivilegesofthedefaultusergroupsorthedefaultrepositoryusers.

30.WhatucandowithDesigner?

Ans:TheDesignerclientapplicationprovidesfivetoolstohelpyoucreatemappings:SourceAnalyzer.Usetoimportorcreatesourcedefinitionsforflatfile,Cobol,ERP,andrelational

sources.WarehouseDesigner.Usetoimportorcreatetargetdefinitions.TransformationDeveloper.Usetocreatereusabletransformations.MappletDesigner.Usetocreatemapplets.MappingDesigner.Usetocreatemappings. Note:TheDesignerallowsyou toworkwithmultiple toolsatone time.Youcanalsowork inmultiplefoldersandrepositories

31.WhataredifferenttypesofTracingLevelsuhvinTransformations?Ans:TracingLevelsinTransformations:LevelDescriptionTerseIndicateswhentheInformaticaServerinitializesthesessionandits

components.Summarizessessionresults,butnotatthelevelofindividualrecords.NormalIncludesinitializationinformationaswellaserrormessagesandnotificationof

rejecteddata. Verbose initialization Includes all information provided with the Normal setting plusmore extensive

informationaboutinitializingtransformationsinthesession.VerbosedataIncludesallinformationprovidedwiththeVerboseinitializationsetting.

Toaddaslightperformanceboost,youcanalsosetthetracing leveltoTerse,writingtheminimumofdetailtothesessionlogwhenrunningasessioncontainingthetransformation.

31(i).Whatthedifferenceisbetweenadatabase,adatawarehouseandadatamart?Ans:Adatabaseisanorganizedcollectionofinformation.Adatawarehouseisaverylargedatabasewithspecialsetsoftoolstoextractandcleansedatafromoperationalsystemsandtoanalyzedata.Adatamartisafocusedsubsetofadatawarehousethatdealswithasingleareaofdataandisorganizedforquickanalysis.

32.WhatisDataMart,DataWareHouseandDecisionSupportSystemexplainbriefly?Ans:DataMart:

Adatamartisarepositoryofdatagatheredfromoperationaldataandothersourcesthatisdesignedtoserveaparticular

communityofknowledgeworkers.Inscope,thedatamayderivefromanenterprisewidedatabaseordatawarehouseorbemorespecialized.Theemphasisofadatamartisonmeetingthespecificdemandsofaparticulargroupofknowledgeusersintermsofanalysis,content,presentation,andeaseofuse.Usersofadatamartcanexpecttohavedatapresentedintermsthatarefamiliar.Inpractice,thetermsdatamartanddatawarehouseeachtendtoimplythepresenceoftheotherinsomeform.However,mostwriters using the term seem to agree that thedesign of a datamart tends tostartfromananalysisofuserneedsandthatadatawarehousetendstostartfromananalysisofwhatdataalreadyexistsandhowitcanbecollectedinsuchawaythatthedatacanlaterbeused.Adatawarehouseisacentralaggregationofdata(whichcanbedistributedphysically)adatamartisadatarepositorythatmayderivefromadatawarehouseornotandthatemphasizeseaseofaccessandusability for a particular designed purpose. In general, a data warehouse tends to be a strategic butsomewhatunfinishedconceptadatamarttendstobetacticalandaimedatmeetinganimmediateneed.

DataWarehouse:Adatawarehouse is a central repository for all or significant parts of the data that an enterprise's

Note:Bydefault,thetracinglevelforeverytransformationisNormal.



variousbusinesssystemscollect.ThetermwascoinedbyW.H.Inmon.IBMsometimesusestheterm"informationwarehouse."Typically, a datawarehouse is housed on an enterprise mainframe server. Data from various onlinetransactionprocessing(OLTP)applicationsandothersourcesisselectivelyextractedandorganizedonthedata warehouse database for use by analytical applications and user queries. Data warehousingemphasizes the capture of data from diverse sources for useful analysis and access, but does notgenerally start from the pointofview of the end user or knowledge worker who may need access tospecialized,sometimeslocaldatabases.Thelatterideaisknownasthedatamart.datamining,Webmining,andadecisionsupportsystem(DSS)arethreekindsofapplicationsthatcanmakeuseofadatawarehouse.

DecisionSupportSystem:A decision support system (DSS) is a computer program application that analyzes business data andpresentsitsothatuserscanmakebusinessdecisionsmoreeasily.It isan"informationalapplication"(indistinctiontoan"operationalapplication"thatcollectsthedatainthecourseofnormalbusinessoperation).

Typicalinformationthatadecisionsupportapplicationmightgatherandpresentwouldbe:ComparativesalesfiguresbetweenoneweekandthenextProjectedrevenuefiguresbasedonnewproductsalesassumptionsTheconsequencesofdifferentdecisionalternatives,givenpastexperienceinacontextthatisdescribedA decision support system may present information graphically and may include an expert system orartificial intelligence (AI). It may be aimed at business executives or some other group of knowledgeworkers.

33.WhatrthedifferencesbetweenHeterogeneousandHomogeneous?Ans:HeterogeneousHomogeneousStoredindifferentSchemasCommonstructure

StoredindifferentfileordbtypesSamedatabasetypeSpreadacrossinseveralcountriesSamedatacenterDifferentplatformnH/Wconfig.SameplatformandH/Wareconfiguration.

34.HowdoyouuseDDLcommandsinPL/SQLblockex.Accepttablenamefromuseranddropit,ifavailableelsedisplaymsg? Ans: To invoke DDL commands in PL/SQL blocks we have to use Dynamic SQL, the Package used isDBMS_SQL.

35.WhatrthestepstoworkwithDynamicSQL?Ans:OpenaDynamiccursor,ParseSQLstmt,Bindi/pvariables(ifany),ExecuteSQLstmtofDynamicCursorand

ClosetheCursor.

36. Which package, procedure is used to find/check free space available for db objects liketable/procedures/views/synonymsetc?Ans:ThePackageisDBMS_SPACETheProcedureisUNUSED_SPACETheTableisDBA_OBJECTSNote:Seethescripttofindfreespace@c:\informatica\tbl_free_space

37.DoesinformaticaallowifEmpIdisPKeyinTargettblandsourcedatais2rowswithsameEmpID?Ifuuselookupforthesamesituationdoesitallowtoload2rowsoronly1?Ans:=>No,itwillnotitgeneratespkeyconstraintvoilation.(itloads1row)=>EventhennoifEmpIdisPkey.

38. If Ename varchar2(40) from 1 source(siebel), Ename char(100) from another source (oracle) and thetargetishavingNamevarchar2(50)thenhowdoesinformaticahandlesthissituation?HowInformaticahandlesstringandnumbersdatatypessources?

39.Howdoudebugmappings?Imeanwheredouattack?

40.HowdouqrytheMetadatatablesforInformatica?

41(i).Whendouuseconnectedlookupnwhendouuseunconnectedlookup?Ans:

ConnectedLookups:Aconnected Lookup transformation is part of themappingdata flow.With connected lookups, you canhavemultiplereturnvalues.Thatis,youcanpassmultiplevaluesfromthesamerowinthelookuptableoutoftheLookuptransformation.Commonusesforconnectedlookupsinclude:=>Findinganamebasedonanumberex.FindingaDnamebasedondeptno=>Findingavaluebasedonarangeofdates=>Findingavaluebasedonmultipleconditions



UnconnectedLookups:AnunconnectedLookuptransformationexistsseparatefromthedataflowinthemapping.Youwriteanexpressionusingthe:LKPreferencequalifiertocallthelookupwithinanothertransformation.Somecommonusesforunconnectedlookupsinclude:=>Testingtheresultsofalookupinanexpression=>Filteringrecordsbasedonthelookupresults=>Markingrecordsforupdatebasedontheresultofa lookup(forexample,updatingslowlychanging

dimensiontables)=>Callingthesamelookupmultipletimesinonemapping

41(ii).WhatrthedifferencesbetweenConnectedlookupsandUnconnectedlookups?Ans: Although both types of lookups perform the same basic task, there are some importantdifferences:

Partofthemappingdataflow.Separatefromthemappingdataflow.Canreturnmultiplevaluesfromthesamerow.Returnsonevaluefromeachrow.Youlinkthelookup/outputportstoanotherYoudesignatethereturnvaluewiththeReturnport(R).transformation.Supportsdefaultvalues.Doesnotsupportdefaultvalues.Ifthere'snomatchforthelookupcondition,theIfthere'snomatchforthelookupcondition,theserverserverreturnsthedefaultvalueforalloutputports.returnsNULL.Morevisible.ShowsthedatapassinginandoutLessvisible.Youwriteanexpressionusing:LKPtotellofthelookup.theserverwhentoperformthelookup. Cache includesall lookupcolumnsused in the Cache includes lookup/outputports in theLookupconditionmapping(thatis,lookuptablecolumnsincludedandlookup/returnport.inthelookupconditionandlookuptablecolumnslinkedasoutputportstoothertransformations).42.Whatuneedconcentrateaftergettingexplainplan?Ans:The3mostsignificantcolumnsintheplantablearenamedOPERATION,OPTIONS,andOBJECT_NAME.Foreachstep,thesetelluwhichoperationisgoingtobeperformedandwhichobjectisthetargetofthatoperation.Ex:**************************TOUSEEXPLAINPLANFORAQRY...**************************SQL>EXPLAINPLAN2SETSTATEMENT_ID='PKAR02'3FOR4SELECTJOB,MAX(SAL)5FROMEMP6GROUPBYJOB7HAVINGMAX(SAL)>=5000

Explained.

**************************TOQUERYTHEPLANTABLE:**************************SQL>SELECTRTRIM(ID)||''||2LPAD('',2*(LEVEL1))||OPERATION3||''||OPTIONS4||''||OBJECT_NAMESTEP_DESCRIPTION5FROMPLAN_TABLE6STARTWITHID=0ANDSTATEMENT_ID='PKAR02'7CONNECTBYPRIORID=PARENT_ID8ANDSTATEMENT_ID='PKAR02'9ORDERBYID

STEP_DESCRIPTION

ConnectedLookupUnconnectedLookup



0SELECTSTATEMENT1FILTER2SORTGROUPBY3TABLEACCESSFULLEMP

43.HowcomponentsareinterfacedinPsoft?Ans:

44.HowdoudotheanalysisofanETL?Ans:

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45.WhatisStandard,ReusableTransformationandMapplet?Ans:Mappingscontaintwotypesoftransformations,standardandreusable.Standardtransformationsexist

withinasingle mapping.Youcannot reuseastandard transformationyoucreated inanothermapping,norcanyou

createashortcuttothattransformation.However,oftenyouwanttocreatetransformationsthatperformcommon tasks, suchas calculating theaverage salary inadepartment.Sincea standard transformationcannot beusedbymore thanonemapping, youhave to set up the same transformation each timeyouwanttocalculatetheaveragesalaryinadepartment.

Mapplet:Amapplet isa reusableobject that representsa setof transformations. It allowsyou toreusetransformationlogic and can contain as many transformations as you need. A mapplet can contain transformations,reusabletransformations,andshortcutstotransformations.

46.HowdoucopyMapping,Repository,Sessions?Ans:Tocopyanobject(suchasamappingorreusabletransformation)fromasharedfolder,presstheCtrlkeyanddraganddropthemappingintothedestinationfolder.

Tocopyamappingfromanonsharedfolder

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