DFD Checklist


There are many errors that may occur when drawing data flow diagrams. Here is a check list to help you avoid some of the major difficulties.
  • External entities must be people or systems that send information to or accept information form the system to be engineered
  • Data flows must always be labelled with the data they contain. Do not put verbs in the data flow description as this implies a process
  • Parent and child diagrams should be consistent. Do not shows a data flow coming from or to an external entity on a level 1 DFD that isn’t shown on the context diagram (and vice versa).
  • Check the direction of data flows to and from data stores
  • Make sure each process has at least one input and one output
  • Each data store should have at least one input and one output on the DFDs somewhere
  • Each process name should start with a verb
  • Where a process has only two data flows (one input and one output) then check it. Usually a data flow has been omitted.

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