New Customer Information DFD Symbology DeMarco-Yourdon Symbology Gane-Sarson Examples Process Data Store Entity Data Flow 6.1 Create Employee Payroll Check Customer New Customer Information Inventory File D7

DFD for Peeling an Apple 1.0 Get Apple Storage S1 Peeling Device S2 2.0 Peeling Device 4.0 Hold 3.0 Wash 6.0 Discard Peel 5.0 Peel Apple With 7.0 Send Peeled To Processor Disposal Processed System Unwashed Apple Washed Apple Peeling Device Apple Peel Apple Peel Peeled Apple

Context-Level Diagram Employee Payroll System Employee Tax Form Payroll Report Time Sheet Employee Payroll Check Employee Accounting Department

Employee Payroll Record Level-0 DFD 1.0 Create Weekly Payroll Record Employee Data File S1 S2 2.0 Compute Paycheck 3.0 Prepare Summary 4.0 Tax Form Accounting Department Employee Record Paycheck Data Payroll Record Payroll Report Employee Paycheck Employee Tax Form Time Sheet Hours Worked Employee Payroll Record

Level-1 DFD Employee Accounting Department 1.0 Create Weekly Payroll Record Employee Data File S1 Employee Tax Form Payroll Data File S2 2.1 Compute Gross Pay 2.3 Check 2.2 Net 3.2 Print Summary 3.1 Sort Records by Employee 4.2 Tax Form 4.1 Calculate Deductions Employee Paycheck Employee Payroll Time Sheet Employee Record Gross Pay Data Net Pay Hours Worked Payroll Record Sorted Records Payroll Report Employee Accounting Department

Partial Level-n DFD 4.1.2 Calculate Non-tax Deductions 4.1.3 Retirement Allowance 4.2.1 Employee Vacation Pay 4.1.1 Payroll Tax 4.2.2 Print Tax Form Data Employee Tax Form Record Employee Data

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.

ANSI Flowchart Symbology Program Library Manual Oper. Punch Card Source Document Multiple Documents Tape File Disk File Database Sort Extract Merge Decision Termination

System Flowchart Order-Entry Dept. Correct Member Orders Order Errors Input Member Order Edit Program Valid Sort by # Sorted Member Orders Member Order Error Report Correct Order Errors

Functional Primitive 4.1.2 Calculate Non-tax Deductions 4.1.3 Retirement Allowance 4.2.1 Employee Vacation Pay 4.1.1 Payroll Tax 4.2.2 Print Tax Form Data Employee Tax Form Record Employee Data

Non-Probabilistic Decision Tree Process Name Condition 1 (true) Condition 2 (false) Condition 1 (false) Condition 2 (true) 1 2 Action 1 Action 2 Action 3 Action 4

Decision Tree Example 3.25+ 6 < 3.25 5 12% 4 15% M 3 10% Yes F Surcharge Rating < 25 yrs. No 25 yrs. + Yes 1 2 10% 20% 7% 0% 3 4 5 6 F M 15% 12% < 3.25 3.25+ Driver Age Accident Free Gender Driver’s Educ. College H.S. GPA

State-Transition Diagram Error 2. Operating 1. Idle S5. Major Cleared S1. ON button Pushed S3. Error Condition Detected S2. OFF button pushed S4. Minor

Problem 1 DFD Insurance Claimant Review Client History Verify Claim 1.0 2.0 3.0 Insurance Claimant Claims Manager Home Office Claims File Verify Claim Review Client History Issue Claim Payment Insurance Claim Claim Payment Amount Paid Monthly Claims Analysis Claims Report

Structured English for Process 4.x Process ID Structured English   4.1.1 Multiply GROSS_PAY by FED_TAX_RATE and store in EMP_TAX_DEDUCT. 4.1.2 IF EMP_NONTAX_DEDUCT > 0 THEN append EMP_NONTAX_DEDUCT to employee data. 4.1.3 Multiply GROSS_PAY by .01 and store in EMP_RETIRE. 4.1.4 Multiply CURR_EMP_VACATION by EMP_DAY_RATE and store in EMP_VACATION_PAY.