What do Data Flow Diagrams Consist of?
A data flow is a route by which data may travel from one element of a DFD to another. Data Flows are represented by arrows which are labelled with a simple meaningful name. slide 6 Processes are transformations which change incoming data flows into outgoing data flows. Processes are represented as rectangles which contain a simple description of the process. Each process has a unique reference number. In the early stages it is possible to show where in the organisation the process takes place, however this is a physical constraint imposed by the existing system and should not appear in a completed logical data flow diagram. slide 7 A data store is a repository for data. A data store is represented by an open ended rectangle containing the name of the data store (usually a plural noun such as customers), each data store has a unique reference number prefixed by the letter D.
