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The Advantages of Data Flow Diagrams

By Technology Last updated Friday, June/14/2024

Data flow diagrams are centered around processes, also called bubbles.process flow image by Christopher Hall from Fotolia.com

A data flow diagram is used as a system modeling tool in system analysis and design. A data flow diagram consists of four elements which are the process, flow, store, and terminator. All of these elements are required in a data flow diagram. The most important element in a data flow diagram is the process.

Specific Processes

A data flow diagram shows a process, or bubble, as a circle, oval or rectangle. A process or bubble describes a program function and data flow diagrams provide simple names and numbers to describe the specific program function. By numbering the process and keeping the process names simple, the systems analyst can easily and accurately reference the specific process. Examples of a process are: Calculate a Monthly Salary, Calculate Interest Rate, Print a Report.

A data flow diagram shows a flow as a curved or straight arrow line. On a data flow diagram, the arrow line is labeled to describe data or information that is being moved or processed. The point of the arrow line shows the source and the arrow points to the next process, store, or terminator. With the aid of a data flow diagram, a systems analyst can determine if a system has all the required input data and output data for the process.

A data flow diagram shows a store as two parallel lines. A store is any type of storage for data or information and can refer to any automated database, file or manual file system. A data flow diagram can aid a systems analyst to determine if the data store has the required input data to be processed to generate the needed output data or information. A data flow diagram can assist in determining if the data store is appropriate for the generated output information.

A data flow diagram has many levels that help a systems analyst review a system, process by process. A level 0 data flow diagram is the top-level diagram and consists of only one process. The next level of data flow diagram shows more detail, and as the level goes higher, the more detail is shown. This aids the systems analyst to break apart the details easily and determine any problems that may occur in a system.