examples of DFD | Data Flow Diagram


First, we have to define the DFD:

DFD (Data Flow Diagram): is a uml diagram that shows the data flow and transformation between the activities in the software,

Briefly, DFD has 2 types:

§  Logical DFD: it’s done in the analysis phase, this dfd is conceptual.

§  Physical DFD: it done in the design phase, this dfd has more technical details.


Steps to convert logical DFD to physical DFD:

1.    Processes: decompose each process to a more detailed processes, and put the implementation technology to be used in it.

2.    Data flows: each data flow should have the following details: implementation method(database command if exists, display method if exists, storage method if exists, …etc),

3.    Data stores: determine the type of each data store in the dfd, whether it is a database or a table from database or a file or even a tape or any other form of storage.

All Contributions

Draw a sample context diagram and level-0 data flow diagram of a retail store based on the details below:

Relevant data flows include payment information, receipt, goods sold information, and inventory information. Three data stores are a goods sold file, an inventory file, and daily sales total file. Processes include Transform customer purchase, update goods sold file, update inventory file, update daily sales total file, and produce management reports. Sources/sinks include customer and store manager. 

context diagram:


level 0 diagram:


Context-Level Diagram

level 0 diagram:

context diagram

level 0:



precision tools sells a line of high-quality woodworking tools. when customers place orders on the company's website, the system checks to see if the items are in stock, issues a status message to the customer, and generates a shipping order to the warehouse, which fills the order. when the order is shipped, the customer is billed.

The system also produces various reports.

  • Draw a context diagram for the order system.
  • Draw DFD diagram 0 for the order system.


Idenfity Entities, process, data stores & data flow

  • Entities
    • customer
    • warehouse
    • accounting
  • Processes
    • 1.0 check status
    • 2.0 issues status messages
    • 3.0 generate shipping order
    • 4.0 manage accounts receivable
    • 5.0 produce reports
  • Data stores
    • D1 pending orders
    • D2 accounts receivable
  • data flows
    • 1.0
      • order
      • in-stock request
      • order data
      • status data
    • 2.0
      • status message
    • 3.0
      • shipping order
      • order data
    • 4.0
      • invoice
      • shipping confirmation
      • payment
      • accounting data
    • 5.0
      • accounts receivable data
      • order data
      • inventory reports


Context Diagram:

DFD level 0 diagram:

“Almosafer Travel Agency is planning to develop a new system to connect passengers with airline companies. The system will allow passengers to search for a flight by specifying the date of travelling, city of departure, and city of arrival. The system then will provide the passenger with several flight options to select from. After selecting a flight, the passenger has to enter personal details such as full name and id number to proceed to payment. When the passenger completes the payment process, they will receive a confirmation and a ticket from the airline company. In addition to sending confirmation and a ticket to the passengers, airline companies should be able to add new flights to the system, and update or delete an existing flight. They also should be able to receive a daily list of all passenger names and details in each flight.”

Draw a Context diagram:

Draw a DFD Level 0 diagram:

total contributions (9)

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