A data flow model is diagramatic representation of the flow and exchange of information within a system. Data flow models are used to graphically represent the flow of data in an information system by describing the processes involved in transferring data from input to file storage and reports generation.
A data flow model may also be known as a data flow diagram (DFD).
Techopedia explains Data Flow Model
As information converts data through software, it is modified by a series of transformations. These transformations are then depicted through a graphical representation of processes that are applied as data transforms the input it receives by creating a data flow output.
A data flow diagram takes business processes and activities and uses them to create a clear illustration of how data flows through a system. DFDs represent the flow of data from external entities into a single system by moving and storing data from one process to another. Through the use of data flow diagrams, a system can be decomposed into subsystems, and subsystems can be further decomposed into lower-level subsystems. Each subsystem represents a process or activity in which data is processed. Once the lowest level is reached, processes can no longer be decomposed.
Data flow modeling can be used to identify a variety of different things, such as:
Information that is received from or sent to other individuals, organizations, or other computer systems
Areas within a system where information is stored and the flows of information within the system are being modeled
The processes of a system that act upon information received and produce the resulting outputs