Data flow diagrams (DFDs) graphically represent the flow of data through a system. DFDs show how data moves between processes and are used to analyze data flow through business processes. A DFD was proposed by Larry Constantine and uses simple notations like data flows, data stores, processes, and external entities to model the flow of data within a system without including physical details.

3. Graphical representation of the
"flow" of data
A DFD shows the flow of data
through a system
Data flow diagrams were proposed
by Larry Constantine.
Visualization of data processing
(structured design).
It is therefore quite different from a
flowchart.

4. Data flow diagram
Data Flow Diagram (DFD) is graphical
representation of flow of data/info. It is used to show
how data is moved between different processes.
Which graphically represent the relation between
processes and data.
Data Flow Analysis
The stress is mainly on data analysis. After the flow of
data through business processes is data flow analysis.
While handling transactions and finish by tasks, data
are input, processed, stored retrieved used, change and
output. Data flow analysis studies the use of data in
each event.

6. Physical Data flow diagram
• Physical characteristics include
- Names of people
- Forms and document Name
- Names of department
- Master and transaction files
- Equipments and devices used
- Locations
• Most comprehensive and useful approach to developing an accurate
and complete description of current system begins with the development
of a physical DFD

7. Data flow diagram
Data Flow Diagram (DFD) is graphical
representation of flow of data/info. It is used to show
how data is moved between different processes.
Which graphically represent the relation between
processes and data.
Data Flow Analysis
The stress is mainly on data analysis. After the flow of
data through business processes is data flow analysis.
While handling transactions and finish by tasks, data
are input, processed, stored retrieved used, change and
output. Data flow analysis studies the use of data in
each event.

8. • Four simple notations are sufficient to finish a DFD. They are:-
Data flow
Data store Process
External
entities

9. Data flow diagram
External
Entity
Process
Process
Process
Process
External
Entity
Process

10. Simple graphic technique
Helps in defining the
boundaries
Communicating current
system
As a part of system
documentation file
Explains the logic behind the
DF within the system

11. Physical consideration
are left out
Confusion about the
system
Different DFDs model
have different symbols
Process is slow