Data Flow Diagrams (DFDs) are charts that represent the transfer of information between various compartments of a specific system. DFDs are used when designing a project plan because they are easily understood visual aides. Many individuals adapt a basic DFD to draw up custom plans. All of these diagrams depict the same four elements: actors, processes, data flow and data stores; with the same relation: data flows into a system where it is processed by specific entities and then stored.
1-Choose a system to diagram. Establish the actors, processes, data flows and data stores. (i.e Who will handle the data? What form does the data take? Is the data stored or discarded? What processing occurs in your system?)
2-Place the initial actor at the top of the chart; this is the person who creates the data. Use a box to highlight the text if necessary; most DFDs use square borders to indicate actors. These are called nodes.
3-Draw an arrow from the initial actor to the first process.
4-Continue drawing arrows from process to process. Draw multiple arrows if the data goes in multiple directions simultaneously. Label the arrows if the data changes form between processes. Attach additional actors to processes if more data is input.
5-Continue until the data flows into a storage system; this may be a physical file cabinet, electronic storage box or trash can. Distinguish “data” storage” from “actors” by using a distinctive border or color.
6-Draw an arrow from processes to actors. Ensure every actor accepts and produces data; if the entity only receives data then it is “data storage” and should be labeled accordingly.
7-Review the chart and remove erroneous data flow. Add additional nodes and processes as needed. Translate the hand-drawn chart to a DFD creation program or recreate flow chart with word processing software.