7-9 minutes<\/p>\n
A data flow diagram (DFD) represents the flow of information through a system. DFDs quickly became a popular way to visualize the major steps and data involved in software-system processes. They were used to show data flow in a software system, although they could, in theory, be applied to business process modeling. DFDs were useful to document the major data flows or to explore a new high-level design in terms of data flow.<\/p>\n
A data-flow diagram (DFD) is a way of representing a flow of data of a process or a system (usually an information system), for example:<\/p>\n
In other words, it shows how data is processed by a system in terms of inputs and outputs. DFD is built using standardized symbols. There are several notations ford is playing data-flow diagrams.<\/p>\n
The DFD notation draws on graph theory, originally used in operational research to model workflow in organizations. DFD originated from the Activity Diagram used in the SADT (Structured Analysis and Design Technique) methodology at the end of the 1970s.DFD popularizers include Edward Yourdon, Larry Constantine, Tom DeMarco, Chris Gane, and Trish Sarson.<\/p>\n
Different people use different notations to represent processes, data stores, data flow and external entities of the DFD. The most commonly used two different types of notations are by Yourdon & Coad or Gane & Sarson.<\/p>\n
DFD uses 4 basic symbols to represent the flow of the diagram. They are<\/p>\n
The Gane &Sarson method stresses the identification of each node to help reference process narratives that further define each component either in plain text or pseudocode.<\/p>\n
Yourdon and Coad \/ DeMarco Notation Yourdon and Coad method includes components for creating data-flow diagrams and also object state diagrams. Some unique attributes of their DFD notation include:<\/p>\n