Data Flow Diagrams (DFD) is a diagram that uses notations or symbols to portray the network system between the functions related to each other with the flow and storage of data (Adi Nugroho, 2011).

DFD is often used to describe an existing system or a new system that will be developed logically without considering the physical environment in which the data flows or where the data will be stored. One advantage of using a data flow diagram is easier for the user are less mastered the field of computers to understand the system that will be done.

DFD consists of a context diagram and level diagram. Context diagram is a diagram that consists of a process and describe the scope of a system. Context diagram is the highest level of the DFD that describes the entire input to the system or the output of the system. In the context diagram is usually only one process. There should be no stores in the context diagram. Detailed diagram is a diagram that describes the process of what is in the diagram above level.

DFD Components
The components of the DFD is as follows:
  1. External Entity
    External entities (entities) in the external environment that the system can be a person, organization or other systems that are in the external environment that will provide input or receive output from the system.
  2. Data flow
    The flow of data flow between processes, data storage and outer unity (External entity). This data flow shows the flow of data that can be input to the system or the result of a process system.
  3. Process
    A process is an activity or work done by people, machines or computers from the results of a stream of data that goes into the process flow of data to be generated out of the process.
  4. Data Storage
    Data storage is a data storage that can be:
    • A file or database in a computer system.
    • An archive or manual records.
    • A table reference manual.
    • An agenda or a book.