Using Data Model Patterns to Build High-Quality Data Models

8/2/2019 Using Data Model Patterns to Build High-Quality Data Models

1/12

February2009 1

UsingDataModelPatternstoBuildHighQualityDataModels

AlexanderLubyanskyAnalyst,ProjectPerformanceCorporation

Abstract

ThecreationofhighqualitydatamodelsiscriticallyimportanttoITprojectsthatrequiredatabasedesignor

redesign.Thereisnouniversallyrecognizedsetofrulesforthedesignofdatamodels,asidefromsuchconceptsas

normalization.MatthewWest(1996)providesonewellrespectedandconcisesetofrulesforbuildingahigh

qualitydatamodel.DavidHay(1996)expandsonthisconceptofdatamodelrulestoproposethatgooddata

modelsarebuiltfrompatterns.

ThispapercontainsconciseexplanationsofbothWestsrulesandHayspatterns.Thefirstsectionexplainsthe

basicfeaturesofhighqualityandlowqualitydatamodels.ThesecondsectionexplainseachofWestsrules

supportedbyillustrationsandwrittenexampleswherenecessary.Thefinalsectiondescribesthestructureand

functionofHaysUniversalDataModel,listsitspracticalapplications,andshowshowpatternsareusedtocreatea

genericmodelofanorganizationanditsactivities.

Introduction

Adatabasearchitectneedstoknowhowtobuildadatamodelinordertomakeanorganizationaldatabasefrom

scratch,consolidateexistingdatabases,orimproveanexistingdatabase.Ideally,ahighqualitydatamodelmust:

Fituserrequirements.Beunderstandabletotheuser.Bestableandflexibleenoughtoexpandandchangealongwithbusinessprocesses.Bereusable.Bereadyforconnectiontootherdatamodelsusedbytheorganization.

Similarly,alowqualitydatamodellikelycontainssomeoralloftheseflaws:

Thereisalackofnormalizationtothirdnormalform.Businessrulesarebuiltintothestructureofthedatamodel,makingithardtochangethedatamodelalongwiththebusiness.

Entities(thingsthatwillbecometablesinaphysicaldatamodel)areunidentifiedormisidentified.Datastructuresandfunctionalityarereplicated.

Tomaximizethechancesofbuildingahighqualitydatamodel,thedatabasearchitectneedstofollowsomerules

forbuildingthedatamodel.Inthispaper,twosetsofrulesareexplained.ThefirstisWests(1996)sixrulesof

highqualitydatamodels.ThesecondisHays(1996)useofdatamodelpatternstobuilddatamodelsthatconform

tothesixrules.

TheSix

Rules

of

High

Quality

Data

Models

Inhis1996paper,DevelopingHighQualityDataModels,MatthewWestoutlinesseveralrulesforcreatinghigh

qualitydatamodels.Westsrulesarecompatiblewithbutdifferentfromthebasicsofdatabasenormalization,

astheydealmorewiththestyleorartofcreatingdatamodels.

DavidHaycommentsontheserules(2005,January1)andusesthemasafoundationforhis1996bookondata

modelpatterns.Thesixrulesareparaphrasedbelow.


2/12

UsingDataModelPatternstoBuildHighQualityDataModels,Lubyansky

February2009 2

1. Entitytablesshouldrepresenttheunderlyingnatureofanobject,notitsrole.2. Entitytablesshouldbepartofsubtype/supertypehierarchies.3. Activitiesandassociationsshouldbeentitytables,notrelationships.4. Relationshipsshouldonlyattachthenounentitytableslikepeople,places,andassetstoactivityand

associationentitytables.

5. Candidateattributesoftablesshouldbecheckedtoseeiftheyareforeignkeys.6. Tablesotherthanpureintersectiontablesshouldhaveartificiallygenerateduniqueidentifiers.Therestofthissectiondescribeseachoftheserules,illustratingexampleswithdiagramsasnecessary.All

diagramsinthispaperaredesignedasconceptualdatamodelsinSybasePowerDesigner12.5(Sybase,2008).

AlldiagramsusetheInformationEngineeringNotation.Inthisnotation,theendsofarelationshipindicate

cardinality(lineisone,crowsfootismany)andoptionality(dashismandatory,opencircleisoptional).

Entitiesarenamedassingularandthelabelsontheendsofrelationshipshavethenearesttableastheoriginof

the

relationship

and

the

farthest

table

as

the

destination.

For

example,

the

English

sentences

to

describe

Figure

2

are:AWorkOrdermustbeperformedbyexactlyonePersonandAPersonmustperformzeroormoreWork

Orders.

1.Entitytablesshouldrepresenttheunderlyingnatureofanobject,notitsrole.Entitiesshouldrepresenttheunderlyingnaturesoftheirbusinessconcepts,nottherolesofthosebusiness

concepts.Forexample,aPersonmaybeconsideredanimportantbusinessentity,sincepeopleperformthework

ofanorganization.However,aPersonmayperformoneormorerolesinanorganization.

Asanotherexample,aTechnicianmayperformaMaintenanceOrdertorepairtheorganizationsequipment.

Similarly,anEngineermayperformaProductionOrdertoproducesomenewequipmentfortheorganization.A

ManagermaycommissionaProjectOrdertostartsomeorganizationalproject.Aconceptualdiagramofthese

entitiesandtheirrelationshipsisshowninFigure1.

Figure1.Entitiesbasedonroles.

WhileitispossibletorepresentthesebusinessentitiesandrelationshipsasinFigure1,itispreferabletorepresent

themasinFigure2.InFigure1,theentitiesarebasedontherolesofvariouspeopleandworkorders.InFigure2,

theentitiesarebasedontheunderlyingnaturesoftheentities.

performs

performed by

performs

performed by

performs

performed by

TechnicianMaintenance Order

Production Order Engineer

Project Order Manager


3/12


February2009 3

APersoncorrespondstoaphysicalhumanbeingwhohasmanydifferentrolesandabilitiesintheorganization.A

WorkOrdercorrespondstoapaperorelectronicdocumentauthorizingsomesortofwork.

Figure2.Entitiesbasedontheunderlyingnaturesofthebusinessconceptstheyrepresent.

UsingPersonandWorkOrderasentitiesispreferabletousingtheirvariousrolesasentities.Thisallowsthe

databasearchitecttoseparatebusinesslogicfromstructure,reduceredundancy,andimproveflexibilityofthe

datamodel.Forexample,withFigure2,entitiesmaybeaddedtorepresentoneormorerolesforaPersonor

WorkOrder.

Similarly,itbecomeseasiertorelateentitiestoeachother.Forexample,aPersonmaybeaManagerofanother

PersonoraProjectOrdermayincludeseveralProductionOrders.ThedatamodelinFigure2isbettersuitedto

addingthis

kind

of

new

structure

while

keeping

the

data

model

flexible

and

stable.

2.Entitytablesshouldbepartofsubtype/supertypehierarchies.Theuseofsubtypesandsupertypesisaveryusefulwaytomakedatamodelsmorepowerfulandflexible.Theuse

ofsubtypesandsupertypesinadatamodelissomewhatakintotheuseofclasshierarchiesinobjectoriented

programming,althoughtheentityrelationshipstructureofadatamodelisnotobjectoriented.

Figure3showsanexampleofahierarchyofentities.Inthishierarchy,thebottomrightcornerofthediagram

containsthesupertypeParty,withsubtypesofPerson,Organization,andsoon(thereasonsforvariousdisplay

conventionsarediscussedinHay,1996).PersonandOrganizationinheritParty,whileEmployeeand

NonEmployeeinheritPerson.

Inaphysicaldatamodel,thewaytobuildasubtype/supertypehierarchyisbyputtingafieldinthesubtypetable

thatpointstotheprimarykeyofthesupertypetable.Theoretically,itispossibletohavemanytypesof

subtype/supertyperelationships

corresponding

to

all

the

possible

inheritances

in

object

oriented

programming,

butthissubjectisbeyondthescopeofthispaper.

Figure3.TheinheritancestructureofPartyinInformationEngineeringNotation.

performsperformed by

PersonWork Order

Person

Party

Employee

Organization

NonEmployee


4/12


February2009 4

ThedatamodelinFigure3hasseveraladvantages.Thefirstadvantageisthatitallowsbetternormalizationofthe

fieldsoftherelevantbusinessconcepts.InFigure3,aPartyisagenericorganizationalentitythatmayenterinto

contracts,haveidentifyinginformation,etc.Thisentityprobablyhasonlyafewattributes,suchasName.Of

course,aPersonhasaFirstNameandLastName,whileanOrganizationhasaNameandmaybeaLegal

Nameor

Common

Name.

In

this

case,

it

makes

sense

to

put

the

attributes

into

the

appropriate

subtype

of

the

entity.NamesprobablyexistatthelevelofPersonandOrganization.

Similarly,anEmployeeofanorganizationlikelyhasattributesthatpertainonlytohisemployersuchasEmployee

IdentificationNumber.ItmakessensetoputthisattributeatthelevelofEmployeeandNonEmployee,rather

thanatthelevelofPerson.Becauseofthesubtype/supertypehierarchyinthedatamodel,attributesexistonlyat

theappropriatelevelofthehierarchyandfortheappropriatenodeinthehierarchy.

Thesecondadvantageofthesubtype/supertypehierarchyisthatitallowsrelationshipstobeappropriately

distributedtodifferententitiesinthehierarchy.Forexample,peopleandorganizationsmayhavethesame

interactionswitheachother.APersonmaybuyaproductfromanotherPerson,anOrganizationmaybuya

productfromaPerson,etc.

Itisusefultohaveahigherleveltypeforinteractionssuchasordering,cooperativerelationships,andsoon.Inthis

case,Party

may

be

either

aPerson

or

an

Organization,

allowing

acontract

or

purchase

order

to

be

made

between

anytwoparties,regardlessoftheirsubtypes.

Figure4.TheinheritancestructureofPartywithinheritancelineshiddentomimicBarker'sNotation.

Asadiagrammingnote,whileclosertoUnifiedModelingLanguage(UML)notation,thenotationinFigure3

becomescumbersomewithmultiplesubtypesandmultiplerelationships.Hay(1996)prefersthemorecompact

andintuitiveBarker'sNotationshowninFigure4. InFigure4,allentitiesareconnectedasinFigure3,buta

subtypeislocatedinsideitssupertypeinthediagram.Thiscompactnotationisusedinallsubsequentdiagrams

inthispaper.InSybasePowerDesigner,itiseasytouseInformationEngineeringNotationtomimicBarker's

Notationbyhidingrelationshiplinesandsuperimposingentitiesatoponeanother.

AlternativeconventionsandtechniquesforcreatingentityrelationshipdiagramsinUMLproperarediscussedin

depthbyHay(2008,September3;2008,October1;2008,November1;2008,December1).

Party

Person

Employee

Organization

NonEmployee


5/12


February2009 5

3.Activitiesandassociationsshouldbeentitytables,notrelationships.Oneofthemostfrequentplaceswherebusinesslogicishiddeninthestructureofadatamodelisinitsactivities

andassociations.Thedatabasearchitectusuallyputsthenounsoftheorganizationintothedatamodelthe

people,equipment,supplies,andplacesrelevanttotheorganizationwhilehidingtheverbsoftheorganization

in

the

relationships

between

these

noun

entities.

Theseverbsincludealloftheactivitiesandassociationsofthenounentities.Forexample,aPersonmaybe

employedforanOrganization.ThismayberepresentedbyformingarelationshipbetweenaPersonentityandan

Organizationentity.

However,ifthereisaneedtorepresentmorethanthefactthatPersonXcurrentlyisemployedbyOrganization

Y,theassociationcalledEmploymentneedstobemadeintoitsownentity.Thisway,thedatabasearchitectmay

specifythestartandenddatesofemployment,thetypeofemployment(fulltime,part time,contractor),and

otherpropertiesoftheemployment.Figure5showsanexampleofthisdatamodelruleappliedtotheactivitiesandassociationsoftheequipmentused

byahypotheticalscientificresearchorganization.Aspartofitsactivities,thisorganizationusesvariouskindsof

equipmenttomeasureandtransmitenvironmentaldataatvariousgeographicsites.

Thethree

main

supertype

entities

in

this

model

are

Asset,

Activity,

and

Site.

Their

relationships

are

that

an

Asset

performsanActivityandanAssetislocatedataSite.Allotherrelationshipsarebetweenvarioussubtypeentities.

Forexample,asubtypeofAssetisEquipment(ascomparedtoassetslikebuildings,lotsofinventory,etc.)andits

subtypesareInstrumentandTransmitter.AnInstrumentmayperformtheActivityofTestand/orData

Dissemination,whileaTransmittermayperformtheActivityofTransmission.

ThesepiecesofEquipmentmayalsobephysicallyconnectedtoeachotherviaaDataConnection.Instruments

maybeconnectedviaaDataCollectionconnectionandInstrumentsmaybeconnectedtoTransmittersviaaData

TransmissionConnection.Finally,eachDataConnectionisrecordedatthelocationofaStation,asubtypeofSite.

InFigure5,theassociationbetweenAssetandSiteisonlyrepresentedasarelationshipasanintentionalmistake

forillustrativepurposes.Ifthedatabasearchitectdecidesthisassociationiscomplexorimportantenough,hemay

createanentitycalledAssetPlacementtoactasanintersectionentitybetweenAssetandSite.Thischoiceisa

matterof

practicality

versus

conformity

to

the

rules.

Totrulyfollowthethirdruleofdataquality,AssetPlacementmustberepresentedasanentity.Thereareatleast

tworeasonsforthischoiceofrepresentation.First,AssetPlacementisanactivitythatisperformedbythe

organization.Activitiesandproceduresaresignificantbusinessentitiesandmustbemodeledassuchtofully

representalltheimportantdataoftheorganization.

Second,activitiesandprocedurescanoftenhavemanytomanyrelationshipswiththeentitiestowhichtheyare

linked.InFigure5,AssettoSiteisamanytoonerelationship.ThisassumesthatanAssetisonlyatoneSiteata

timeandthatitisonlyimportanttorepresentthemostrecentplacementstartandendtimesoftheAsset.Quite

often,thehistoryofactivitiesisimportanttorecordrelationallysothedatamodelmustrepresenttherelationship

betweenAssetandSiteasmanytomany,withAssetPlacementholdingthestartandendtimeinformationfor

eachplacementofanAssetataSite.

Ultimately,Figure

5shows

some

activities

(Activity,

Test,

Data

Dissemination,

and

Transmission)

and

associations

(DataConnection,DataCollection,DataTransmission)asseparateentitiesfromtheAssetsdoingtheactivitiesor

participatingintheassociations.Thisallowsforamorecompactandflexiblerepresentationofthecomplexityof

theseactivitiesandassociations.


6/12


February2009Figure5.ActivitiesandAssociationsfortheAssetentity.

contains

located at

performs

performed by

hosts the occurrence of

occurs at

Asset

Equipment

Data Connection

Site

the reference for

refers tothe

from

the reference for

refers to

the re

to

Data Transmission

Data Collection

Activity

performed by

performed by

performed by

Transmission

Data Dissemin ation

Test

Station


7/12


February2009 7

4.Relationshipsshouldonlyattachthenounentitytableslikepeople,places,andassetstoactivityandassociationentitytables.Thisruleissimplyanextensionofthethirdrule.Ifallactivitiesandassociations(verbs)areentitiesinadata

model,all

noun

entities

are

indirectly

linked

through

these

activity/association

entities.

By

following

rules

three

andfour,adatamodelexplicitlyandseparatelyrepresentsandconnectsthesenounsandverbs.

5.Candidateattributesoftablesshouldbecheckedtoseeiftheyareforeignkeys.Thefifthruleofdataqualityasksthedatabaseanalysttocheckifentitiesattributesshouldthemselvesbesplitoff

asnewentities.Theproblemhereiswhenabusinessviewisencodedintoanentitysattributes.Forexample,

Figure6showsonepotentialsetofattributesfortheentityParty.

Figure6.ThecollapsedPartyentity.

TheattributesofPartyrelatetodifferentbusinessconceptssuchascontactinformationandemployment.Also,if

PartymaybeeitheranOrganizationoraPerson,thenattributeslikeNameareclumsy.Ingeneral,Figure6is

poorlynormalized.Asidefrommattersofpracticality,ifthedatabasearchitectwantstocloselyfollowthefifthrule

ofdataquality,shewillexpandFigure6intosomethinglikeFigure7.

Figure7showstheentitiesandrelationshipsneededtorepresentalloftheattributesinFigure6.InFigure7,Party

hassubtypesOrganizationandPerson.Organizationhasaparentchildrelationshipwithitself,whilePersonisnow

relationallylinkedtoOrganizationviaEmployment.TheattributeTypefromFigure6isimplementedvia

intersectionentitiesforbothPersonandOrganization.ContactinformationistheseparateentityContactSource,

withsubtypesPhoneandEmail.ThisexpandedrepresentationremovesbusinesslogicoutofthePartyentityand

representsitrelationally.

6.Tablesotherthanpureintersectiontablesshouldhaveartificiallygenerateduniqueidentifiers.Thisfinalruleisdesignedtoavoidtyinginappropriatebusinesslogictotheidentifiersofentities.Whilethe

databasearchitectmayfindattributesthatseemunique,useoftheseattributesasidentifierslimitstheflexibility

ofthedatamodeltofuturechange.

The

best

thing

to

do

is

to

create

a

new

attribute

to

act

as

the

unique

identifier

for

an

entity.

This

unique

identifier

attributemaybesetbythedatabasetohavenorepeatingrecords.Theonlyexceptiontothisruleisan

intersectiontable.Anintersectiontabledoesnotneedtocreateanewuniqueidentifierattribute,sinceitsunique

identifieristhecombinationoftheuniqueidentifiersoftheentitiestowhichitislinked.

Party

Name (Last)

FirstName

Type

StartEmployment

EndEmploymentPhone (Home)

Phone (Cell)

Email

ParentOrg


8/12


February2009 8

Figure7.TheexpandedPartyentity.

DataModelPatterns

TheUniversalDataModelHay(1996)proposesthatthereisaUniversalDataModelforalmostallaspectsofanorganization,asidefromvery

specializedfunctionslikeaccounting.TheUniversalDataModelisthehighestlevelabstractionofagooddata

model.WhiletheUniversalDataModelislargelyatheoreticalmodel,itsummarizesthebasicdatamodelpattern

principles.Figure8showstheUniversalDataModel.

AtthecenterofthisdatamodelistheentityThing.AThingispotentiallyanyentityinthedatamodelthat

describessomethinginthebusinessworldthedatamodelistryingtorepresent.AThingmaybeoneofthe

organizationsnounslikePerson,Asset,Site,andWorkOrderoroneoftheorganizationsverbslike

Employment,Placement,orDataConnection.

EveryThingbelongstoaThingClass.AThingClassisthestructuraldefinitionoftheThing.TheentityThingClass

allowsthedataarchitecttospecifythestructureandbehaviorofeveryThinginthedatamodelwithinthe

database.Forexample,oneThingcalledCarmaycontainindividualcars.TheThingClassforCarmaybecalledCar

Model.TherecordsinCarModelmaybemodelsofcarssuchas2009ToyotaCamryandtherecordsinCarmay

beindividualcarssuchasaparticularToyotaCamryintherealworld.

can be reached via

is useful to reach

Contact Source Party

describes

is described b y

hasincludes

has

includes

describes

is described by

is the parent of

is the child of

is categorized by

categorizes

describes

is described by

Person

FirstNameLastName

Organization

OrgName

EmploymentStartDt

EndDt

Employment Type

Employment Type

Organization Categorization

Organization Type

Organization Type

Phone

PhoneNumber

Phone Type

Email

EmailAddress


9/12


February2009 9

Figure8.TheUniversalDataModel.

ThingClassallowstheassignmentofAttributesandtheirValuestoaThing.Forexample,aparticularToyotaCamry

mayhaveanattributesuchasPowerSteeringwhichmayeitherbepresent(1)orabsent(0).IntheUniversal

DataModel,eachattributegoesintotheAttributeentity,whichisassignedtoaThingClassviatheAttribute

AssignmententityandpopulatedforaThingwithaValue.Thisisahighlynormalizeddatastructurewhere

AttributeisseparatelyconnectedtoThingandThingClassviaintersectionentities.

IntheCarexample,PowerSteeringmaybeanattributeinCarAttribute.TheCarAttributeAssignmententity

maythenbepopulatedsuchthatevery2009ToyotaCamryhastheCarAttributePowerSteering.AgivenCar

whoseCarClassis2009ToyotaCamrymaythenhaveaCarAttributeValueforPowerSteering.

InadditiontoAttributes,aThingmayalsohaveoneormoreRelationshipstootherThings.Theserelationshipsare

activitiesandassociations.Forexample,aCarmaybeparkedinaGarage.Inthisexample,CarandGarageare

ThingsandParkingistheRelationship.TheRelationshipalsohasaRelationshipType,whichisthedefinitionofthe

Relationship,much

like

with

Thing

and

Thing

Class.

In

the

example,

the

Parking

Relationship

may

be

the

RelationshipType.

AllentitiesintheUniversalDataModelmaybesubtypesorsupertypesofotherentities,sothiswholestructure

mayworkatmultiplelevels.Forexample,CarmayhaveasupertypeofVehicle,andCarModelmayhavea

supertypeofVehicleType(car,airplane,boat,etc.).

Attributesandtheirvaluesmaythusbeassignedatmultiplelevels.Attributesrelevantonlytocars(likepresence

ofapowersteeringoption)mayberepresentedatthelevelofCarandCarModel,whileattributesatthelevelof

vehicles(likeweight,maximumspeed,etc.)mayberepresentedatthelevelofVehicleandVehicleType.

described by

for

given

of

subject to

of

the structural definition of

to

the structural definition of

of

on one side of

from

on the other side of

to

the definition of

an example of

ThingRelationship

Relationship Type

Thing Class

Attribute Assignment

Attribute

Value


10/12


February2009 10

Finally,theUniversalDataModelisametamodel,amodelofdatamodelsingeneral.Therefore,theUniversalData

Modelisrecursivewithregardtoallitsentitiesandrelationships.AThingClassmayalsobeaThing,thushavingits

ownAttributeValuesandRelationships(CarModeltoGarageType,forexample).ARelationshipmayalsobea

ThingandsomayanAttribute.ThepossibilitiesareendlessaslongasthebasicpatternoftheUniversalData

Modelapplies.

PracticalapplicationsofdatamodelpatternsThebasicbuildingblocksoftheUniversalDataModelmaybeusedtodevelopmanypractical,complexdata

modelsofthebusiness.Forexhaustiveexamples,thesourceisHays1996book,butthereareseveralexamples

accessibleonlinefromHaysprofessionalwebsite(1997)andonlinearticlesinTheDataAdministrationNewsletter.ThemainbusinessareasthatHaymodelsincludethefollowing:

Thepaperworkoforganizations,includingcontracting,accounting,anddocumentmanagement.Althoughusuallythesefunctionsareusuallyperformedbycommercialofftheshelfsoftware,adatabasearchitectmay

needtodesignthemfromscratch.Inthiscase,suchmodelsprovideusefulexamplesofthesuperstructureof

thesevariousbusinessfunctions.

People,organizations,andplacesandtherelationshipsbetweenthem,suchasgeographicplacement,employment,

and

organizational

reporting

structures.

Physicalassetslikebuildings,piecesofequipment,andtypesofinventorygoods(likenutsandbolts).Thesemodelsdescribeindetailhowtorepresenttheassembly/compositionofphysicalthingsaswellastheirlogical

andphysicalconnectionswitheachother.

Variousproceduresandactivitiesconductedbypeopleandorganizations.Theseworkordersmayinvolvebuilding,maintaining, repairing,orsomehowalteringotherimportantentitiessuchasassets.Thesemodels

alsodiscusshowtorepresentmultipartworkactivitieslikeprojectsaswellasthedetailsofassigningand

billingresourcestoworkorders.

Advancedproceduresandactivitiesthatrequireveryspecializeddatamodels.Examplesarelaboratorymeasurements,materialrequirementplanning,andprocessmanufacturing.Thesedatamodelscoververy

advancedlogicalconceptslikehowtotrackcontinuousflowsofliquids.

AnexampledatamodelbuiltfrompatternsFigure9containsanexampledatamodelofanorganizationanditsactivitieswhichisbuiltfromdatamodel

patterns.Thismodelonlyshowsthemostimportantentitiesofagenericorganizationandonlyatthehighestlevel

ofthesubtype/supertypehierarchy.

ThepeopleandorganizationsinFigure9arerepresentedbyParties,whichmaybeplacedatSites.Thephysical

thingsoftheenterpriseAssetsmayalsobeplacedatSites.ASitemayrepresentanysizespaceorlocationand

isgroundedtotheEarthviaoneormoreGeographicAreas.

ThewayPartiesinteractwithAssetsisviaWorkOrders.WorkordersmayinvolvePartiesengaginginActivities

and/orAssetsengaginginActivities.ThisallowsforsuchvariedActivitiesasanorganizationstartingaproject,a

technicianinstallinganinstrument,oraninstrumentpassivelycollectingenvironmentaldata.

Theentities

Asset

and

Activity

are

each

likely

to

be

heterogeneous

and

complicated

enough

to

require

Parameters,

andthushaveThingClassentities:AssetTypeandActivityType.

Whileacompletedatamodelneedsmanymoreentities,thebasicsofenterprisearerepresentedinFigure9.

Figure9showsthebasicpeople,places,things,andactivitiesofthegenericenterprise.


11/12


February2009Figure9.AnexampledatamodelbuiltwiththeUniversalDataModelpattern.

location o

location of

located at

place of

embodied in

an example of

the responsibility of

the authorization for

authorized by

embodied in

an example of

described by

for

subject to

from

defined by

to

subject to

from

subject to

of

charged with

charged to

subject to

ofcharged with

charged to

described by

for

defined by

to

Pl

Geog

Asset

Asset Type

Activity

Activity Type

Work Order

Parameter Assignm ent

Parameter Value

Parameter

Asset Type Usage

Asset Usage


12/12


February2009 12

AbouttheAuthor

AlexanderLubyanskyisanAnalystatProjectPerformanceCorporation.Hecomesfromaresearchand

developmentbackgroundwithexperienceinbothITandresearch.Thisexperienceincludesrequirements

elicitation,datamodelingandanalysis,decisionsupportsystemdesign,businessintelligence,andcomputer

simulation.For

more

information

on

this

white

paper,

please

contact

Alexander

by

email

at

[email protected].

References

Hay,D.C.(2008,December1).UMLasaDataModelingNotation,Part4.TheDataAdministrationNewsletter.RetrievedDecember24,2008fromhttp://www.tdan.com/viewarticles/9219.

Hay,D.C.(2008,November1).UMLasaDataModelingNotation,Part3.TheDataAdministrationNewsletter.RetrievedDecember24,2008fromhttp://www.tdan.com/viewarticles/8914.

Hay,D.C.(2008,October1).UMLasaDataModelingNotation,Part2.TheDataAdministrationNewsletter.RetrievedDecember24,2008fromhttp://www.tdan.com/viewarticles/8457.

Hay,D.C.(2008,September3).UMLasaDataModelingNotation,Part1.TheDataAdministrationNewsletter.RetrievedDecember24,2008fromhttp://www.tdan.com/viewarticles/8589.

Hay,D.C.(2005,January1).DataModelQuality:WhereGoodDataBegins.TheDataAdministrationNewsletter.RetrievedDecember24,2008fromhttp://www.tdan.com/viewarticles/5286.

Hay,D.C.(1997).AdvancedDataModelPatterns.EssentialStrategies,Inc. RetrievedDecember24,2008fromhttp://www.essentialstrategies.com/publications/modeling/advanceddm.htm.

Hay,D.C.(1996).DataModelPatterns:ConventionsofThought.NewYork:DorsetHousePublishing.Sybase.(2008).PowerDesignerDataModelingSoftwareTool.RetrievedDecember24,2008from

http://www.sybase.com/products/modelingdevelopment/powerdesigner.

West,M.(1996).DevelopingHighQualityDataModels(Version2.0).EPISTLE.RetrievedDecember24,2008from

http://www.matthewwest.org.uk/documents/princ03.pdf.

Documents

Using Data Model Patterns to Build High-Quality Data Models