AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
Appendix C
The University Lab: Conceptual Design, Verification,
Logical Design, and Implementation
Discussion Focus
Howjoisjoajodatabasejodesignjoverified,joandjowhyjoisjosuchjoverificationjonecessary?
Usejoourjodetailedjoanswerjotojoquestionjo1jotojofocusjoclassjodiscussionjoonjodatabasejodesignjoverificatio
n.joStressjothatjothejoverificationjoprocessjousesjothejoinitialjoERjomodeljoasjoajocommunicationjotool.
Thejodesignerjomayjobeginjothejoverificationjoprocessjobyjodescribingjothejoorganization'sjooperationsjotoj
oitsjoendjousers,jobasingjothejodetailedjodescriptionjoonjothejoinitialjoERjomodel.joNext,joexplainjohowjothej
ooperationsjowilljobejosupportedjobyjothejodatabasejodesign.joStressjothatjothejodesignjomustjosupportjoth
ejoend-
userjoapplicationjoviews,jooutputs,joandjoinputs.joPointsjotojobejoaddressedjoincludejosuchjoquestionsjoas:
Isjothejodescriptionjoaccurate?joIfjonot,jowhatjoaspectsjoofjothejodescriptionjomustjobejocorrected?
Doesj o thej o modelj o supportj o thej o end-
userj o requirements?j o Ifj o not,j o whatj o aspectsj o ofj o thej o end-
userojrequirementsjohavejonotjobeenjoaddressedjoorjohavejobeenjoaddressedjoinadequately?
Keepjo injo mindjothatjo evenjo ajomodeljo thatjo perfectlyjo addressesjo alljo initiallyjo determinedjoendjo userjo
requirementsjoisjolikelyjotojoneedjoadjustmentsjoasjothosejoendjousersjobeginjotojounderstandjothejoramific
ationsjoofjothejodatabasejodesign'sjocapabilities.joInjomanyjocases,jothejoendjousersjomayjolearnjowhatjoth
ejoorganization'sjoprocessesjoandjoproceduresjoactuallyjoare,jothusjoleadingjotojonewjorequirementsjoandj
othejoperceptionjoofjonewjoopportunities.joThejodatabasejodesignerjomustjokeepjosuchjolikelyjodevelopme
ntsjoinjomind,joespeciallyjoifjo(s)hejoworksjoasjoajodatabasejodesignjoconsultant.jo(Anticipationjoofjosuchjod
evelopmentsjomustjobejofactoredjointojothejocontractjonegotiationsjoforjoconsultingjofees.)
Discussjothejorolejoofjothejosystemjomodules.
1
, AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
Thej o usej o ofj o systemj o modulesj o canj o hardlyj o bej o overemphasizedj o inj o aj o databasej o designj o envir
onment.j o Stressjothesejomodulejocharacteristicsjoandjofeatures:
Modulesjorepresentjosubsetsjoofjothejodatabasejomodel:joSmallerjo"pieces"joarejomorejoeasil
yjounderstood.
Modulesjoarejoself-
containedjoandjoaccomplishjoajospecificjosystemjofunction;joifjosuchjoajosystemjofunctionjom
ustjobejomodified,jootherjofunctionsjoremainjounaffected.
Modulesjofitjointojoajomodularjodatabasejodesign,jowhichjoisjomorejoeasilyjomodifiedjoandjoa
daptedjotoojnewjocircumstances.joBecausejomodificationjoeffortsjoarejofocusedjoonjoajodataba
sejosubset,joproductivityjoofjobothjodesignersjoandjoapplicationjodevelopersjoisjolikelyjotojobe
joenhanced.
Modulejointerfacesjomustjobejoclearjoifjothejomodulesjoarejoexpectedjotojoworkjowelljowithinjothejooveralljosystem.
2
, AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
AnswersjotojoReviewjoQuestions
1. Whyjomustjoajoconceptualjomodeljobejoverified?joWhatjostepsjoarejoinvolvedjoinjothejoverificationjoprocess?
Thejoverificationjoofjoajoconceptualjomodeljoisjocrucialjotojoajosuccessfuljodatabasejodesign.joThejoveri
ficationjoprocessjoallowsjothejodesignerjotojocheckjothejoaccuracyjoofjothejodatabasejodesignjoby:
Re-examiningjodatajoandjodatajotransformations.
Enablingjo thejo designerjo toj o evaluatejo thej o designj o efficiencyjo relativej o toj o thej o endjo
user'sj o andjosystem'sjodesignjogoals.
Keepjoinjomindjothat,jotojoajolargejoextent,jothejobestjodesignjoisjothejoonejothatjoservesjothej o end-
userjorequirementsjobest.joForjoexample,joajodesignjothatjoworksjowelljoforjoajomanufacturingjofirmjo
mayjonotjofitjothejoneedsjoofjoajomarketingjoresearchjofirm,joandjovicejoversa.
Thejoverificationjoprocessjohelpsjothejodesignerjotojoavoidjoimplementationjoproblemsjolaterjoby:
Validatingjothejomodel'sjoentities.jo(Rememberjothejominimaljodatajorule.)
Confirmingjoentityjorelationshipsjoandjoeliminatingjoduplicate,jounnecessary,joorjoimpr
operlyjodefinedjorelationships.
Eliminatingjodatajoredundancies.
Improvingjothejomodel'sjosemanticjoprecisionjotojobetterjorepresentjoreal-worldjooperations.
Confirmingjothatjoalljouserjorequirementsjo(processing,joperformance,joorjosecurity)joarejomet.
Verificationjoisjoajocontinuousjoactivityjoinjoanyjodatabasejodesign.joThejodatabasejodesignjoprocessjoi
sjoevolutionaryjoinjonature:joItjorequiresjothejocontinuousjoevaluationjoofjothejodevelopingjomodeljoby
joexaminingjothejoeffectjoofjoaddingjonewjoentitiesjoandjobyjoconfirmingjothatjoanyjodesignjochangesjo
enhancejothejomodel'sjoaccuracy.
Thejoverificationjoprocessjorequiresjothejofollowingjosteps:
1. Identifyjothejodatabase'sjocentraljoentity.
Thej o centralj o entityj o isj o thej o mostj o importantj o entityj o inj o ourj o database,j o andj o mos
tj o ofj o thej o otherjoentitiesjodependjoonjoit.
3
, AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
2. Identifyjoandjodefinejoeachjomodulejoandjoitsjocomponents.
Thej o designerj o dividesj o thej o databasej o modelj o intoj o smallerj o setsj o thatj o reflectj o thej o
dataj o needsj o ofjoparticularjosystemsjomodulesjosuchjoasjoinventory,joorders,jopayroll,joetc.
3. Identifyjoandjodefinejoeachjoofjothejomodule'sjoprocesses.
Specifically,jo thisjo stepjo requiresjo thejo identificationjo andjo definitionjo ofjo thejo databasejo transactions
thatjorepresentjothejomodule'sjoreal-worldjooperations.
4
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
Appendix C
The University Lab: Conceptual Design, Verification,
Logical Design, and Implementation
Discussion Focus
Howjoisjoajodatabasejodesignjoverified,joandjowhyjoisjosuchjoverificationjonecessary?
Usejoourjodetailedjoanswerjotojoquestionjo1jotojofocusjoclassjodiscussionjoonjodatabasejodesignjoverificatio
n.joStressjothatjothejoverificationjoprocessjousesjothejoinitialjoERjomodeljoasjoajocommunicationjotool.
Thejodesignerjomayjobeginjothejoverificationjoprocessjobyjodescribingjothejoorganization'sjooperationsjotoj
oitsjoendjousers,jobasingjothejodetailedjodescriptionjoonjothejoinitialjoERjomodel.joNext,joexplainjohowjothej
ooperationsjowilljobejosupportedjobyjothejodatabasejodesign.joStressjothatjothejodesignjomustjosupportjoth
ejoend-
userjoapplicationjoviews,jooutputs,joandjoinputs.joPointsjotojobejoaddressedjoincludejosuchjoquestionsjoas:
Isjothejodescriptionjoaccurate?joIfjonot,jowhatjoaspectsjoofjothejodescriptionjomustjobejocorrected?
Doesj o thej o modelj o supportj o thej o end-
userj o requirements?j o Ifj o not,j o whatj o aspectsj o ofj o thej o end-
userojrequirementsjohavejonotjobeenjoaddressedjoorjohavejobeenjoaddressedjoinadequately?
Keepjo injo mindjothatjo evenjo ajomodeljo thatjo perfectlyjo addressesjo alljo initiallyjo determinedjoendjo userjo
requirementsjoisjolikelyjotojoneedjoadjustmentsjoasjothosejoendjousersjobeginjotojounderstandjothejoramific
ationsjoofjothejodatabasejodesign'sjocapabilities.joInjomanyjocases,jothejoendjousersjomayjolearnjowhatjoth
ejoorganization'sjoprocessesjoandjoproceduresjoactuallyjoare,jothusjoleadingjotojonewjorequirementsjoandj
othejoperceptionjoofjonewjoopportunities.joThejodatabasejodesignerjomustjokeepjosuchjolikelyjodevelopme
ntsjoinjomind,joespeciallyjoifjo(s)hejoworksjoasjoajodatabasejodesignjoconsultant.jo(Anticipationjoofjosuchjod
evelopmentsjomustjobejofactoredjointojothejocontractjonegotiationsjoforjoconsultingjofees.)
Discussjothejorolejoofjothejosystemjomodules.
1
, AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
Thej o usej o ofj o systemj o modulesj o canj o hardlyj o bej o overemphasizedj o inj o aj o databasej o designj o envir
onment.j o Stressjothesejomodulejocharacteristicsjoandjofeatures:
Modulesjorepresentjosubsetsjoofjothejodatabasejomodel:joSmallerjo"pieces"joarejomorejoeasil
yjounderstood.
Modulesjoarejoself-
containedjoandjoaccomplishjoajospecificjosystemjofunction;joifjosuchjoajosystemjofunctionjom
ustjobejomodified,jootherjofunctionsjoremainjounaffected.
Modulesjofitjointojoajomodularjodatabasejodesign,jowhichjoisjomorejoeasilyjomodifiedjoandjoa
daptedjotoojnewjocircumstances.joBecausejomodificationjoeffortsjoarejofocusedjoonjoajodataba
sejosubset,joproductivityjoofjobothjodesignersjoandjoapplicationjodevelopersjoisjolikelyjotojobe
joenhanced.
Modulejointerfacesjomustjobejoclearjoifjothejomodulesjoarejoexpectedjotojoworkjowelljowithinjothejooveralljosystem.
2
, AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
AnswersjotojoReviewjoQuestions
1. Whyjomustjoajoconceptualjomodeljobejoverified?joWhatjostepsjoarejoinvolvedjoinjothejoverificationjoprocess?
Thejoverificationjoofjoajoconceptualjomodeljoisjocrucialjotojoajosuccessfuljodatabasejodesign.joThejoveri
ficationjoprocessjoallowsjothejodesignerjotojocheckjothejoaccuracyjoofjothejodatabasejodesignjoby:
Re-examiningjodatajoandjodatajotransformations.
Enablingjo thejo designerjo toj o evaluatejo thej o designj o efficiencyjo relativej o toj o thej o endjo
user'sj o andjosystem'sjodesignjogoals.
Keepjoinjomindjothat,jotojoajolargejoextent,jothejobestjodesignjoisjothejoonejothatjoservesjothej o end-
userjorequirementsjobest.joForjoexample,joajodesignjothatjoworksjowelljoforjoajomanufacturingjofirmjo
mayjonotjofitjothejoneedsjoofjoajomarketingjoresearchjofirm,joandjovicejoversa.
Thejoverificationjoprocessjohelpsjothejodesignerjotojoavoidjoimplementationjoproblemsjolaterjoby:
Validatingjothejomodel'sjoentities.jo(Rememberjothejominimaljodatajorule.)
Confirmingjoentityjorelationshipsjoandjoeliminatingjoduplicate,jounnecessary,joorjoimpr
operlyjodefinedjorelationships.
Eliminatingjodatajoredundancies.
Improvingjothejomodel'sjosemanticjoprecisionjotojobetterjorepresentjoreal-worldjooperations.
Confirmingjothatjoalljouserjorequirementsjo(processing,joperformance,joorjosecurity)joarejomet.
Verificationjoisjoajocontinuousjoactivityjoinjoanyjodatabasejodesign.joThejodatabasejodesignjoprocessjoi
sjoevolutionaryjoinjonature:joItjorequiresjothejocontinuousjoevaluationjoofjothejodevelopingjomodeljoby
joexaminingjothejoeffectjoofjoaddingjonewjoentitiesjoandjobyjoconfirmingjothatjoanyjodesignjochangesjo
enhancejothejomodel'sjoaccuracy.
Thejoverificationjoprocessjorequiresjothejofollowingjosteps:
1. Identifyjothejodatabase'sjocentraljoentity.
Thej o centralj o entityj o isj o thej o mostj o importantj o entityj o inj o ourj o database,j o andj o mos
tj o ofj o thej o otherjoentitiesjodependjoonjoit.
3
, AppendixjoCjoThejoUniversityjoLab:
ConceptualjoDesignjoVerification,joLogicaljoDesign,joandjoImplementa
tion
2. Identifyjoandjodefinejoeachjomodulejoandjoitsjocomponents.
Thej o designerj o dividesj o thej o databasej o modelj o intoj o smallerj o setsj o thatj o reflectj o thej o
dataj o needsj o ofjoparticularjosystemsjomodulesjosuchjoasjoinventory,joorders,jopayroll,joetc.
3. Identifyjoandjodefinejoeachjoofjothejomodule'sjoprocesses.
Specifically,jo thisjo stepjo requiresjo thejo identificationjo andjo definitionjo ofjo thejo databasejo transactions
thatjorepresentjothejomodule'sjoreal-worldjooperations.
4
