Enter prise ModelingOutlineModelingEnter prise Architecture FrameworkER Modelsfour lectures on this topic followDFD Modelsone lecture followsStatechar tsone lecture followsOther MethodologiesEnter prise Modeling ModelingMotivation - WhyModel?If you can’t model,youcan’t comprehend.If you can’t comprehend,youcan’t control.Dual Goals:✯ analysis & conceptualization✯ presentation©Copyr ight 2008-9-25, E Robertson 2Enter prise Modeling ModelingModels,Methods,and MediaAModel•descr ibes (aspects of) a business ororganization•separates & organizesGood Modeling requires good Methodologies,which•encompass data, process,decisionsnot necessarily all in one methodology•are richly expressive•provide for levels of analysis•provide for levels of detail•havesimple representationsModeling Medium•same termaspainting media: oil, pastel, etc.•both for mal and visualGeneral PrincipleUse minimal for malism to startwith, addingspecial notation only when unavoidable.©Copyr ight 2008-9-25, E Robertson 3Enter prise Modeling ModelingEnter prise Architecture Framework•ameta-model for organizations◊ infor mation systems◊ aircraft construction◊ regional planning◊ the entire enter prise•organizes material according to◊ interrogatives◊ levelofabstraction◊ levelofdetail•Originally proposed byJohn Zachman andoften given his name.©Copyr ight 2008-9-25, E Robertson 4Enter prise Modeling Enter prise Architecture FrameworkEnter prise Architecture in InfoSys CoursesArchitecture provides•classification of models•interrelation of models•systemization of analysisArchitecture is•specified above the individual project•sometimes specified above the individualorganization•inter national standards being developede.g. supply-chain management©Copyr ight 2008-9-25, E Robertson 5Enter prise Modeling Enter prise Architecture FrameworkEnter prise Architecture MediumNotation:•simple 2D gridStructure:•column labels: interrogatives•row labels: roles / abstraction levels•detail: recursioncell in gridmay hold other grids©Copyr ight 2008-9-25, E Robertson 6Enter prise Modeling Enter prise Architecture FrameworkThe Six InterrogativesIt has long been recognized that six questions areimpor tant in infor mation gather ing and analysis:•What?•How?•Where?•Who?•When?•Why?These same interrogatives can be used to classifyaspects of the analysis.©Copyr ight 2008-9-25, E Robertson 7Enter prise Modeling Enter prise Architecture FrameworkSix Interrogatives & Infor mation SystemsThe six interrogatives maybeused to classifyelements of an infor mation system:What?•data / infor mationHow?•function / processWhere?•location / site / facility•networ kWho?•people•organizational structureWhen?•business event•timeWhy?•motivation•goals & objectives•“business rules”©Copyr ight 2008-9-25, E Robertson 8Enter prise Modeling Enter prise Architecture FrameworkLevels: Abstraction⇒Concretenesslevelrole modelConceptual Specifier Enter priseLogical Designer SystemPhysical Implementer TechnologyThis is not the same as levels of detail.Levels of concreteness are orderedInterrogatives are unordered©Copyr ight 2008-9-25, E Robertson 9Enter prise Modeling Enter prise Architecture FrameworkLevels: General ⇒ DetailTop-down decompositionEach levelofdetail has comparable structuree.g. Manufactur ing process (a “How” item) isanalyzed with the same interrogatives:◊ machines used (“What”)◊ production schedule (“When”)◊ subprocesses (“How”)◊ etc.Hence,recursion on frames•paths through nested frames an additionalaspect of structure©Copyr ight 2008-9-25, E Robertson 10Enter prise Modeling Enter prise Architecture FrameworkZachman Framework PictureWhat HowWhere Who When WhySpecifyDesignBuild•Detail achievedby“dr illing-down” in a cell©Copyr ight 2008-9-25, E Robertson 11Enter prise Modeling Enter prise Architecture FrameworkRow1Modeling Methodologies byInterrogativeWhat•Entity Relationship models (ER)static − infor mationHow•Data FlowDiagrams (DFD)dynamic − process•For mal specification languagesusually hard to apply in IS contextWhen•Statechar ts• •••Where•MapsWho•Organization chartsWhy•Decision tables•Business rules (str uctured text)©Copyr ight 2008-9-25, E Robertson 12Enter prise Modeling Enter prise Architecture FrameworkColumn Interaction − Modeling MethodologiesDF and ER are complimentar y.•studying howdata flows tells about itsstr ucture•studying data’sstr ucture tells about its uses.©Copyr ight 2008-9-25, E Robertson 13Enter prise Modeling ER ModelsEntity-Relationship MediumBasic Notation:Entity boxRelationship diamondplus linesAttr ibute textEnriched Notation:•generalizationa Person is a Student or Employee•relationship constraintsa Dependant must be the child of some EmployeeStructure:•ERmodels are flat,•subset to focus on a particular area©Copyr ight 2008-9-25, E Robertson 14Enter prise Modeling ER ModelsEntity-Relationship Model ExampleInfor mation used byaLicense BranchPERSON AUTOOwnsnamebirth_dateididmakemodelyearsome text ...Key:EntityRelationshipAttribute©Copyr ight 2008-9-25, E Robertson 15Enter prise Modeling ER ModelsEntity-Relationship Notation Models ItselfRELNSHIPENTITYEorRATTRIBTHasPartpIsASUPER SUBE-R notation sufficiently powerful to model itself.©Copyr ight 2008-9-25, E Robertson 16Enter prise Modeling DFD ModelsData FlowMediumNotation:Source boxProcess (transfor m) boxwith rounded cornersFile (store) boxopen on rightDestination boxFlowarrowSources and sinks are similar to processes in manyways,butsources and sinks are beyond the control of yoursystem.Structure:‘‘Explosion’’ofprocesses(recursion on structure)With Respect to Lifecyclemodel flowsimplement processes©Copyr ight 2008-9-25, E Robertson 17Enter prise Modeling DFD ModelsData FlowDiagramExampleOperation of a “License Branch”Citizenissuetitledrivers licenseapplicationbill ofsaledrivers licensetitleprocessedtitleapplicationtemporarytitlesource /sinkprocessdata flowLegendPERSON−AUTOprocessdriverslicenseapplicationprocesstitleapplicationstore (database)©Copyr ight 2008-9-25, E Robertson 18Enter prise Modeling Statechar tsStatechar ts•use to specify state-dependent behaviorasub-case of time-dependent behavior•primitives◊ state◊ ev ent•extends finite automata with+concise notation+modular ity©Copyr ight 2008-9-25, E Robertson 19Enter prise Modeling Statechar tsStatechar t