PowerPoint PresentationSlide 2Composite and Elementary Data FlowsData Flows to and from Data StoresIllegal Data FlowsData FlowData StructuresData Structure NotationA Data Structure for a Data FlowData Structure ConstructsData Structure Constructs (concluded)Data Types and DomainsDiverging and Converging Data FlowsSlide 14External AgentsData StoresWhen to Draw Process ModelsClassical Structured AnalysisModern Structured AnalysisStructured Analysis Diagram Progression (1 of 3)Structured Analysis Diagram Progression (2 of 3)Structured Analysis Diagram Progression (3 of 3)CASE TOOLS for DFDs (Sample Screen) from System Architect 2001SoundStage Context DFDSome Ideas – Context DiagramsSoundStage Functional Decomposition DiagramEventsUse CasesUse Case ListUse Case List (continued)Slide 31Event Decomposition Diagram (partial)External Event DFDExternal Event DFD (more complex)Temporal Event DFDSystem DFD (see book for more readable copy)Primitive DFD (see book for more readable copy)Data Structure for a Primitive Data FlowLogic for a Primitive Process8.30 Data to Process CRUD Matrix8.31 Process to Location Association Matrix8C H A P T E RPROCESS MODELING(con’t)Composite and Elementary Data FlowsData Flows to and from Data StoresIllegal Data FlowsAll data flow must begin/end at a processData FlowBusiness processes were designed data flowsComputerizing based on business forms continues the problemsIdentify data flows independent of implementationData conservation – “starving a process” ie. Data flow only contains data used by the processMust precisely define the make up of each data flowData StructuresData flows can be defined by data structures.A data structure is a specific arrangement of data attributes that defines the organization of data contained in a data flow.A data attribute is the smallest piece of data that has meaning to the end-users of a business. Don’t confuse with defining entities – we are defining I/O to each processData Structure Notation = composed of+ and[ .. ] one and only one - 1:1{ .. } Repetition - 1:n(…) OptionalA Data Structure for a Data FlowDATA STRUCTUREORDER=ORDER NUMBER +ORDER DATE+[ PERSONAL CUSTOMER NUMBER, CORPORATE ACCOUNT NUMBER]+SHIPPING ADDRESS=ADDRESS+(BILLING ADDRESS=ADDRESS)+1 {PRODUCT NUMBER+ PRODUCT DESCRIPTION+ QUANTITY ORDERED+ PRODUCT PRICE+ PRODUCT PRICE SOURCE+ EXTENDED PRICE } N+SUM OF EXTENDED PRICES+PREPAID AMOUNT+(CREDIT CARD NUMBER+EXPIRATION DATE)(QUOTE NUMBER)ADDRESS=(POST OFFICE BOX NUMBER)+STREET ADDRESS+CITY+[STATE, MUNICIPALITY]+(COUNTRY)+POSTAL CODEENGLISH ENTERPRETATIONAn instance of ORDER consists of:ORDER NUMBER andORDER DATE andEither PERSONAL CUSTOMER NUMBERor CORPORATE ACCOUNT NUMBERand SHIPPING ADDRESS (which is equivalent to ADDRESS)and optionally: BILLING ADDRESS (which is equivalent to ADDRESS)and one or more instances of:PRODUCT NUMBER andPRODUCT DESCRIPTION andQUANTITY ORDERED andPRODUCT PRICE andPRODUCT PRICE SOURCE andEXTENDED PRICEand SUM OF EXTENDED PRICES andPREPAID AMOUNT andoptionally: both CREDIT CARD NUMBER and EXPIRATION DATEAn instance of ADDRESS consists of:optionally: POST OFFICE BOX NUMBER andSTREET ADDRESS andCITY andEither STATE or MUNICIPALITYand optionally: COUNTRYand POSTAL CODEData Structure ConstructsData StructureSequence of Attributes - The sequence data structure indicates one or more attributes that may (or must) be included in a data flow.Selection of Attributes - The selection data structure allows you to show situations where different sets of attributes describe different instances of the data flow.Repetition of Attributes - The repetition data structure is used to set off a data attribute or group of data attributes that may (or must) repeat themselves a specific number of time for a single instance of the data flow. The minimum number of repetitions is usually zero or one. The maximum number of repetitions may be specified as “n” meaning “many” where the actual number of instances varies for each instance of the data flow.Format by Example(relevant portion is boldfaced)WAGE AND TAX STATEMENT= TAXPAYER IDENTIFICATION NUMBER+ TAXPAYER NAME+ TAXPAYER ADDRESS+ WAGES, TIPS, AND COMPENSATION+ FEDERAL TAX WITHHELD+…ORDER= (PERSONAL CUSTOMER NUMBER, CORPORATE ACCOUNT NUMBER)+ ORDER DATE+…CLAIM= POLICY NUMBER+ POLICYHOLDER NAME+ POLICY HOLDER ADDRESS+ 0 {DEPENDENT NAME+ DEPENDENT’S RELATIONSHIP} N+ 1 {EXPENSE DESCRIPTION+ SERVICE PROVIDER+ EXPENSE AMOUNT} NEnglish Interpretation(relevant portion is boldfaced)An instance of WAGE AND TAX STATEMENTS consists of: TAXPAYER IDENTIFICATION NUMBER and TAXPAYER NAME and TAXPAYER ADDRESS and WAGES, TIPS AND COMPENSATION and FEDERAL TAX WITHHELD and…An instance or ORDER consists of: Either PERSONAL CUSTOMER NUMBER or CORPORATE ACCOUNT NUMBER; and ORDER DATE and…An instance of CLAIM consists of: POLICY NUMBER and POLICYHOLDER NAME and POLICYHOLDER ADDRESS and zero or more instance of: DEPENDENT NAME and DEPENDENT’S RELATIONSHIP and one or more instances of: EXPENSE DESCRIPTION and SERVICE PROVIDER and EXPENSE ACCOUNTData Structure Constructs (concluded)Data StructureOptional Attributes - The optional notation indicates that an attribute, or group of attributes in a sequence or selection date structure may not be included in all instances of a data flow.Note: For the repetition data structure, a minimum of “zero” is the same as making the entire repeating group “optional.”Reusable Attributes - For groups of attributes that are contained in many data flows, it is desirable to create a separate data structure that can be reused in other data structures.Format by Example(relevant portion is boldfaced)CLAIM= POLICY NUMBER+ POLICYHOLDER NAME+ POLICYHOLDER ADDRESS+ ( SPOUSE NAME+ DATE OF BIRTH)+…DATE= MONTH+ DAY+ YEAR+English Interpretation(relevant portion is boldfaced)An instance of CLAIM consists of: POLICY NUMBER and POLICYHOLDER NAME and POLICYHOLDER ADDRESS and optionally, SPOUSE NAME and DATE OF BIRTH and... Then, the reusable structures can be included in other data flow structures as follows: ORDER=ORDER NUMBER…+DATE INVOICE=INVOICE NUMBER…+DATE PAYMENT=CUSTOMER NUMBER…+DATEData Types and DomainsData attributes should be defined by data types and domains.A data type defines what class of data can be stored in an attribute