Material shifts are modeled in systems that are not merely informative. Exceptions are flows where it is clear what information is transferred through the entities that are linked to these flows. The flow should have a name that determines what information (or what material) is being moved. ĭata flow (flow, dataflow) shows the transfer of information (sometimes also material) from one part of the system to another. The process is named in one word, a short sentence, or a phrase that is clearly to express its essence. The symbol of a process is a circle, an oval, a rectangle or a rectangle with rounded corners (according to the type of notation). The process (function, transformation) is part of a system that transforms inputs to outputs. There are several ways to view these DFD components. Analogously, the semantics of transitions from Petri nets and data flows and functions from data-flow diagrams should be considered equivalent.ĭata flow diagram - Yourdon/ DeMarco notationĭFD consists of processes, flows, warehouses, and terminators. 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).
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