What are Data Flow Diagrams?
A quick search on the Web reveals that Data Flow Diagrams (DFDs) are a graphical representation of the flow of data into, around, and out of a system.
Note
Refer to the following links for more information on DFDs:
http://www.agilemodeling.com/artifacts/dataFlowDiagram.htm
http://www.mckinnonsc.vic.edu.au/vceit/designtools/dfd/dfd.htm
Throughout the seventies, various academics developed methodologies for modeling data flows. The one by Gane and Sarson is utilized in the Data Flow Model Diagrams template in Visio. This methodology has the following four elements:
Squares representing external entities, which are sources or destinations of data. These are the places that provide the organization with data, or have data sent to them by the organization (for example, customers, partners, government bodies).
Rounded rectangles representing processes, which take data as input, do something to it, and output it.
Arrows representing the data flows, which can be either...
