PowerPoint PresentationChapter EightProcess ModelingChapter MapModels: Logical and PhysicalWhy Logical System ModelsProcess Modeling and DFDsSimple Data Flow DiagramDifferences Between DFDs and FlowchartsSystems ThinkingProcess ConceptsDecompositionDecomposition DiagramsSlide 13Types of Logical ProcessesFunctionsCommon DFD ErrorsCommon Process Errors on DFDsProblems with Natural EnglishStructured EnglishStructured English Constructs (Part 1)Structured English Constructs (Part 2)Structured English Constructs (Part 3)Policies and Decision TablesA Simple Decision TableData Flows & Control FlowsData Flow Packet ConceptComposite and Elementary Data FlowsData Flows to and from Data StoresSlide 298C H A P T E RPROCESS MODELINGChapter EightProcess ModelingDefine systems modeling and differentiate between logical and physical system models.Define process modeling and explain its benefits.Recognize and understand the basic concepts and constructs of a process model.Read and interpret a data flow diagram.Explain when to construct process models and where to store them.Construct a context diagram to illustrate a system’s interfaces with its work environment.Identify use cases, external and temporal business events for a system.Perform event partitioning and organize events in a functional decomposition diagram.Draw event diagrams and merge those events into a system diagram.Draw primitive data flow diagrams and describe the elementary data flows and processes in terms of data structures and procedural logic (Structured English and decision tables), respectively.Document the distribution of processes to locations.Synchronize data and process models using a CRUD matrix.Chapter MapModels: Logical and PhysicalLogical models show what a system is or does. They are implementation independent; that is, they depict the system independent of any technical implementation.Physical models show not only what a system is or does, but also how the system is (to be) physically and technically implemented. They are implementation dependent because they reflect technology choices.A model is a representation of reality. Just as a picture is worth a thousand words, most models are pictorial representations of reality. Better understand existing system and Document requirements for proposed systemWhy Logical System ModelsLogical models remove biases that are the result of the way the system is currently implemented, or the way that any one person thinks the system might be implemented.Logical models reduce the risk of missing business requirements because we are too preoccupied with technical results.Logical models allow us to communicate with end-users in nontechnical or less technical languages.Process Modeling and DFDsProcess modeling is a technique for organizing and documenting the structure and flow of data through a system’s processes, and/or the logic, policies, and procedures to be implemented by a system’s processes.A data flow diagram (DFD) is a tool (and type of process model) that depicts the flow of data through a system and the work or processing performed by that system. DFDs have become a popular tool for business process redesign.Simple Data Flow DiagramDifferences Between DFDs and FlowchartsProcesses on DFDs can operate in parallel (at-the-same-time)Processes on flowcharts execute one at a timeDFDs show the flow of data through a systemFlowcharts show the flow of control (sequence and transfer of control)Processes on one DFD can have dramatically different timingProcesses on flowcharts are part of a single program with consistent timingSystems ThinkingSystems thinking is the application of formal systems theory and concepts to systems problem solving.DFDs are a tool that supports systems thinking.Process ConceptsA process is work performed on, or in response to, incoming data flows or conditions.A System is a ProcessT h eS y s t e mi s aP r o c e s si n p u t o u t p u ti n p u ti n p u t o u t p u to u t p u tF e e d a c k a n dC o n t r o l L o o pT h e S y s t e m ' s E n v i r o n m e n t( c o n s t a n t l y c h a n g i n g )AP r o c e s sSystem DecompositionDecompositionDecomposition is the act of breaking a system into its component subsystems, processes, and subprocesses. Each level of abstraction reveals more or less detail.Decomposition DiagramsA decomposition diagram or hierarchy chart shows the top-down, functional decomposition of a system.Decomposition DiagramsEach process is either a parent process or a child processA parent must have two or more childrenIn most cases a child may have only one parentA child process may be a parent process as wellTypes of Logical ProcessesA function is set of related and ongoing activities of a business.An event (or transaction) is a logical unit of work that must be completed as a whole (as part of a function).An elementary process (or primitive process) is a discrete, detailed activity or task required to respond to an event. Usually, several such tasks must be completed to respond to an event.FunctionsProcesses that respond to EventsEach event is represented by a respond processGenreate ______________Process _______________Respond to ____________Common DFD ErrorsBlack HolesInputs to a process but no outputMiraclesCreating output with no inputGray HoleInsufficient inputs to create the desired resultsProcesses that depict clerical task or simply moving documents to next locationDFDs should depictComputationsDecisionsOrdering or summarizingOrganizingTriggersStored dataCommon Process Errors on DFDsPROBLEMS WITH NATURAL ENGLISH 1 Source: Adapted from Matthies, Leslie, The New Playscript Procedure, (Stamford, CT: Office Publications, Inc. 1977)Problems with Natural EnglishMany of us do not write well, Many of us are too educated! e graduate has a working vocabulary of around 5,000 words.Some of us write everything like it was a program. Too often, we allow the jargon and acronyms of computing to dominate our language.English statements frequently have an excessive or confusing scope. We overuse compound sentences Too many words have multiple definitions.Too many statements use imprecise adjectives. Conditional instructions can be imprecise. Compound conditions tend to show up in natural English.1. For each CUSTOMER NUMBER in the data store CUSTOMERS: a. For each LOAN in the data store LOANS that matches the above CUSTOMER NUMBER: 1) Keep a running total of NUMBER OF