Data Flow Diagram

Topics: Data flow diagram, Flowchart, Diagrams Pages: 14 (1080 words) Published: August 2, 2013
How to : Data Flow Diagrams (DFDs)

Data Flow Diagrams (DFDs)


Data flow diagram (DFD) is a picture of the movement of data between external entities and the processes and data stores within a system

Order CUSTOMER Status Message Status Data 2.0 Shipping Confirmation

In-Stock Request WAREHOUSE 1.0 Shipping Order

Check Status Order Data D1 Pending Orders 3.0

Issue Status Messages

Order Data Payment Invoice Manage Accounts Receivable 5.0 Accounting Data Accounts Receivable Data 4.0 Order Data

Generate Shipping Order

D2

Accounts Receivable Inventory Reports

Produce Reports

ACCOUNTING

DFD Symbols (Gane & Sarson)
Process

Data Flow Data Store

Source/Sink (External Entity)

Process
1.0
Grade Detail

Grade Report

Produce Grade Report

  

Work or actions performed on data (inside the system) Labels should be verb phrases Receives input data and produces output

Rule 1: Process


Can have more than one outgoing data flow or more than one incoming data flow 1.0

Graded Work Student Grade

Submitted Work

Grade Student Work

3.0

Hours Worked Pay Rate
Calculated Gross Pay

Gross Pay

Rule 2: Process


Can connect to any other symbol (including another process symbol)

1.0
Order

2.0

Accepted Order
Verify Order Assemble Order

Inventory Change

Process: Correct/Incorrect?
5.0
Services Perfomed

Invoice

Create Invoice

Policy Number
Apply Insurance Premium

Payment Amount

2.1

Hours Worked

Calculate Gross Pay

Pay Rate

Data Flow
Deposit

  

Is a path for data to move from one part of the IS to another Arrows depicting movement of data Can represent flow between process and data store by two separate arrows 2.1
Payment Detail Invoice Detail

Post Payment

D1

Accounts Receivable

Data Flow: Correct/Incorrect?
5.0 Post Payment

Courses
Customer Payment

Class List

D2

Daily Payments

Students

Daily Payment

6.0

Prepare Deposit

Data Store
D1 Students

 

Is used in a DFD to represent data that the system stores Labels should be noun phrases

Rule: Data Store


Must have at least one incoming and one outgoing data flow
Customer Payment

D1

Daily Payments

Daily Payment

Data Store: Correct/Incorrect?
2.0

D2

Accounts Receivable

Book Flight

Invoice Detail
Fight Request
3.0

Payment Detail

Passengers

Post Payment

Source/Sink (External Entity)
Order
CUSTOMER

1.0

Invoice

Verify Order

 






External entity that is origin or destination of data (outside the system) Is the singular form of a department, outside organisation, other IS, or person Labels should be noun phrases Source – Entity that supplies data to the system Sink – Entity that receives data from the system

Rule: Source/Sink


Must be connected to a process by a data flow

BANK

Bank Deposit

2.0

Prepare Deposit

Source/Sink: Correct/Incorrect?
PAYROLL DEPARTMENT
CUSTOMER

CUSTOMER

Paycheck

Payment

Payment

EMPLOYEE

3.0

Accounts Receivable

Apply Payment

Rules for Using DFD Symbols


Data Flow That Connects
YES NO

A process to another process

A process to an external entity
A process to a data store An external entity to another external entity An external entity to a data store A data store to another data store

List the errors of this DFD

DF2 E1 1.0 DF5 P2

DF1

DS1 DF3 DF6 DF4 DF2 E1 2.0 P1

Context Diagram
 



Top-level view of IS Shows the system boundaries, external entities that interact with the system, and major information flows between entities and the system. Example: Order system that a company uses to enter orders and apply payments against a customer’s balance

Context Diagram of Order System

Order
CUSTOMER WAREHOUSE

Order Reject Notice Payment Invoice

Picking List

0

Completed Order

Order System

Commission

Bank...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Data Flow Diagrams Essay
  • Data Flow Essay
  • DATA FLOW DIAGRAM Essay
  • Data Flow Diagrams Example Essay
  • Essay on Data Flow Diagram
  • Data Flow Diagram Essay
  • Data Flow Diagram Essay
  • Data Flow Diagram Tutorial Essay

Become a StudyMode Member

Sign Up - It's Free
Divorcio (2017) | Killer Queen - Queen | Harukana Receive