In this KnowledgeKnugget™ you will learn what a Data Flow Diagram is and how to define business processes and functions (functional requirements)You will also learn how to define data components (informational requirements) and stakeholders for your Information Technology (IT) project..

What Is a Dataflow Diagram?

A picture really is worth a thousand words, especially in the world of Business Analysis for IT projects. Try to describe workflows or business processes in natural language and the chances that IT will deliver the solution you want are very small indeed. The challenge is what picture do you need to draw? There are several techniques for drawing business process models or diagrams and each has a specific focus. Data Flow Diagrams (DFDs) represent the workflow or steps within a business process with a focus on the flow and transformation of business data. A DFD is the right choice for business process modeling if you need to understand the creation and consumption of data in the individual business processes.

The depicted process can be manual or automated; it does not matter as far as the diagram is concerned. Every business process is a more-or-less complex sequence of steps that changes something coming in to create something new. As such, it needs input which could be information or any other resource. It uses the input to create output, whether the output is something altogether new or simply an altered version of the original input. Using the input to create the output adds some measurable value to the process. Thus, we often refer to the “value chain” of the organization.

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The data flow diagram shows a business process at some indeterminate level of detail. Some of the processes might be very global whereas others are very specific. If you need to understand how a process works in detail, you can “explode” it to see its internal processes. Because the DFD does not differentiate levels of detail, these “sub-processes” are simply processes that are at a lower level of detail. Each of these internal processes creates and consumes specific data. If you draw a data flow diagram at this more detailed level, you will see internal data flows and data stores that are more specific and detailed as well. Any process at any level of detail is a potential candidate for exploding. The only factor to consider is whether you understand the process sufficiently to predict how change will affect it.

A DFD serves multiple purposes. You might create one to be able to analyze the current situation with the goal of identifying roadblocks and improving efficiency. You might also create one to present and discuss the process with others. You could create a DFD of a proposed business process before you develop detailed processes and supporting IT applications to identify potential issues before they occur. Its principle use is presumably to identify, document, and communicate stakeholder requirements for an IT project.

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