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The process (function, transformation) is part of a system that transforms inputs to outputs. There are several ways to view these DFD components.

DFD components ĭata flow diagram - Yourdon/ DeMarco notationĭFD consists of processes, flows, warehouses, and terminators. DFDs were useful to document the major data flows or to explore a new high-level design in terms of data flow. DFDs were usually used to show data flow in a computer system, although they could in theory be applied to business process modeling.

ĭata-flow diagrams (DFD) quickly became a popular way to visualize the major steps and data involved in software-system processes. DFD popularizers include Edward Yourdon, Larry Constantine, Tom DeMarco, Chris Gane and Trish Sarson. DFD originated from the activity diagram used in the structured analysis and design technique methodology at the end of the 1970s. The DFD notation draws on graph theory, originally used in operational research to model workflow in organizations. Analogously, the semantics of transitions from Petri nets and data flows and functions from data-flow diagrams should be considered equivalent. A special form of data-flow plan is a site-oriented data-flow plan.ĭata-flow diagrams can be regarded as inverted Petri nets, because places in such networks correspond to the semantics of data memories. When using UML, the activity diagram typically takes over the role of the data-flow diagram. The data-flow diagram is a tool that is part of structured analysis and data modeling. The refined representation of a process can be done in another data-flow diagram, which subdivides this process into sub-processes. The notation presented above was described in 1979 by Tom DeMarco as part of structured analysis.įor each data flow, at least one of the endpoints (source and / or destination) must exist in a process. There are several notations for displaying data-flow diagrams. Specific operations based on the data can be represented by a flowchart. A data-flow diagram has no control flow - there are no decision rules and no loops. The DFD also provides information about the outputs and inputs of each entity and the process itself. Data flow diagram with data storage, data flows, function and interfaceĪ data-flow diagram is a way of representing a flow of data through a process or a system (usually an information system).