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Data Flow Diagram

[Process Flow Diagram], DFD Symbols:

Data flow diagram is a pictorial presentation of the data flow of a management information system. In a DFD, the flow of data items from external data or internal data to other external data sink or internal data store by an internal process flow. DFDs are also be utilized for the data process visualization which is known as Structured Design.

A DFD does not provide any information regarding process timings or sequence of the processes. That is why it is not similar to flowchart, which represents flow of control by an algorithm, permitting a reader to determine operations order sequence and its circumstances and it does not describe input & output data type and the data storage procedures.

DFD Symbols or Data Flow Diagrams Notation:

1. Flow:
It is represented by an "Arrow" symbol facing towards data flow direction.

2. Function:
It is represented by a "Circle" symbol.

3. Input-Output:
It is represented by a "Rectangle".

4. Database or File:
It is represented by two horizontal "Parallel Lines".

Context Level DFD: Context level data flow diagram depicts the relationship between the system and external data which behaves as source and sink. It is also known as "level-0-dfd". Under context diagram, the system interacts with outside agents. The entire system under level 0 dfd acts as a single process and there is no description about internal processing. Below given figure shows context level dfd of "Ordering System".


Level 1 DFD (High-level DFD): The high level data flow diagram shows system's division into sub-processes (systems), each describes the data flows with the outside world (agent). It also shows dataflow between each sub-system and performs internal data storage. The purpose of high level dfd is to describe the major processes and their correlations. It can be balanced with its top parent level-0-dfd.

Level 2 DFD (Low-level DFD): Low level dfd shows the decomposition of each process described in high level dfd. It shows all internal workflow and processing to perform each level 1 sub-systems. It also must be balanced with its top parent high level dfd (level 1 dfd).


Please Contact-Us to get all information about data flow diagram symbols and graphical representation with a case study which has described workflow process. One can also get all types of flowchart diagrams as per request. Our designers can implement well defined DFDs, work and process flow charts according to requested dfd systems. And our content writers prepare the system's described case study. Please supply all details in "Message-Field" about required DFD of our contact us page.

DFD for Different Systems | DFD Softwares