So far we have discussed the meaning, use and construction of Data Flow Diagrams. They are very useful for recording the processes and functions that exist in the old and planning the processes and functions that should exist in the new system. The diagrams on their own are insufficient to describe the processes. Behind the diagrams should be a textual description showing detail of all the elements that appear on the diagrams. These are logged into what is known as a data dictionary. Any proprietary CASE tool will have the facility to record these items in a data dictionary.
The DFD’s together with the data dictionary definitions are known as a process model.
