Data Flow Diagram This is a diagram which models the flow of data through the program as it operates The top level is known as a context diagram; in subsequent levels processes are decomposed into subprocesses This recursion ends when a process is deemed small enough to code without error
Data flow diagram; may contain not only data flows, but also processes, data stores and external entities (agents) Note that a DFD is not a GRADE diagram, but GRADE can be used to create models containing the same information as DFDs