Description of Level 1 Data Flow Diagram DFD
A Dataflow diagram is a graphical representation of the flow of data through an information system, can also be used for the visualization of data processing.
The level 1 DFD shows how the system is divided into subsystems (Processes), each of which deals with one or more of the data flows to or from an external agent , and which together provide all the functionality of the system as a whole. It also identifies internal data stores that must be present in order for the system to do its job and show the flow of data between the various parts of the system.
A physical DFD’s represent physical files and transactions while a logical or conceptual DFD can be used to represent business functions or processes.
DFD’s can be of existing system or can describe the requirements for a proposed or planned system. A DFD of an existing system should represent the functions and processes that are already in place. A required system DFD is a diagram of a system that will be implemented in the place of the current one.
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