Using the Data Flow Diagram

A Data Flow Diagram provides a way for an organization (typically an IT or Engineering group) to understand, perfect, or implement a new process or system. It is a way to visually represent the way data flows through the system.

There are two types of Data Flow Diagrams: logical and physical.

  • A logical diagram explains where the data comes from, where it goes, and how it changes

  • A physical diagram explains how the data moves through the system, for example how a data file is copied to a different location.

A Data Flow Diagram is composed of four types of elements:

  • External Entity: an outside system or process that sends and receives data to and from the system. They are typically either the source or the destination for the data. In Bluescape’s template, the green diamond object represents this concept.
  • Data Store: a holding area for information for later use. In Bluescape’s template, the purple square object represents this concept.
  • Process: a procedure that manipulates the data and its flow by taking incoming data, changing it, then producing the data as output. In Bluescape’s template, the blue rectangle object represents this concept.
  • Data Flow: the path the information takes from external sources through processes and data stores. In Bluescape’s template, connectors between objects represent this concept.

There are several best practices to follow when creating a Data Flow Diagram:

  1. Each process should have at least one input and one output.
  2. Each data store should have at least one data flow (connector) in and one data flow out.
  3. A system’s stored data must go through a process.
  4. All processes in a diagram must link to another process or data store.
  5. External entities are typically placed at the edges of the data flow diagram.

To use the Data Flow Diagram Template, identify the process you would like to map, then place the template in your workspace. Use the sample objects to model the process, adding connectors between objects to show the data flow. Change the sample text within each object to give it a descriptive name, and label each connector to capture the data flow details. Continue building your diagram, following the best practice guidelines listed above.

How has the Data Flow Diagram helped you and your team? Hit Reply to this post.