What is a Data Flow Diagram?

A data flow diagram is a structured display of data moving into and out of an information system. The detail within a data flow diagram varies based upon the level assigned to it. Generally, a high-level diagram has only limited information included within it, whereas a lower-level diagram has much more detailed information. This information is used by a development team to manage the data within an information system.

As a team develops an information system, it creates a data flow diagram to document how information will go in and out of the system. Initially, this information is created at a very high level, with only the information system boundaries included within the diagram. As the team develops more of the functionality of the information system, each of the processes within the system may be included on the data flow diagram. This diagram helps the team determine where data will be stored to support the system.

These diagrams serve an important role, since they document how each process within the system accesses information. External systems may also access the data stored within a given information system. These exchanges across systems are documented so that the analysts may track each system interaction. Such interactions are important pieces of information in each organization’s data management process.

Government laws and regulations require management and storage of certain data. These regulations vary by industry. The data flow diagram helps each organization manage how the organization will meet the governmental requirements for data storage. Certain regulations require storage for extended periods of time. The organization must plan accordingly for the appropriate amount of data storage.

Data flow diagrams also help the development team design reports and screen functionality as the information system comes together. The team must know where to collect the data in order to present it to the end user. While the data flow diagram itself does not address system functionality, it does document which system is responsible for storing a specific piece of data. The development team uses the data flow information to describe in its functional documentation where it will look to find information it will display for the end user.

Each organization has a set of data flow diagrams to document the information stored within the organization’s information systems. This set of diagrams is used to properly manage and meet the organization’s data storage requirements. Each organization’s data storage requirements are determined by the organization itself in order to comply with a variety of government regulations and other legal requirements.