1. 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

2. 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

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

4. 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

5. 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

6. 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

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.

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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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.