Presentation on theme: "New Customer Information"— Presentation transcript:
1 New Customer Information DFD SymbologyDeMarco-YourdonSymbologyGane-SarsonExamplesProcessData StoreEntityData Flow6.1CreateEmployeePayrollCheckCustomerNew Customer InformationInventoryFileD7
2 DFD for Peeling an Apple 1.0GetAppleStorageS1Peeling DeviceS22.0PeelingDevice4.0Hold3.0Wash6.0DiscardPeel5.0Peel AppleWith7.0Send PeeledToProcessorDisposalProcessedSystemUnwashed AppleWashed ApplePeeling DeviceApple PeelApple PeelPeeled Apple
7 Rules Governing DFD Construction A process cannot have only outputs – “Miracle.”A process cannot have only inputs – “Black Hole.”The inputs to a process must be sufficient to produce the outputs from the process - (Gray Hole).All data stores must be connected to at least one process.A data store cannot be connected to a source or sink.A data flow can have only one direction of flow. Multiple data flows to and/or from the same process and data store must be shown by separate arrows.If the exact same data flows to two separate processes, it should be represented by a forked arrow.Data cannot flow directly back into the process it has just left.All data flows must be named using a noun phrase.
15 Structured English for Process 4.x Process IDStructured English4.1.1Multiply GROSS_PAY by FED_TAX_RATE and store in EMP_TAX_DEDUCT.4.1.2IF EMP_NONTAX_DEDUCT > 0THEN append EMP_NONTAX_DEDUCT to employee data.4.1.3Multiply GROSS_PAY by .01 and store in EMP_RETIRE.4.1.4Multiply CURR_EMP_VACATION by EMP_DAY_RATE and store in EMP_VACATION_PAY.