DFD (Data Flow Diagram):
DFD is a designing concept used to transform a textual problem into pictorial or graphical form in a hierarchical order.
It describes how data and information are transformed in a system in a pictorial manner.
DFD provides a complete description of:-
(a) What data are processed?
(b) How processing is done?
(c) What data are stored?
(d) Which stored data are used and
(e) Where the result flows?
DFD is top-down designing approach in which
(a)A high-level function is decomposed into a set of easy understandable function.
(b)Each function performed by system is analyzed and decomposed into more detailed description.
- A DFD models a system by using external entities from which data flows to a process which transform the data and creates output data flow which go to other processes or external entities or data stores . From data stores, stored data may also flow to process as inputs.