What does a circle or rectangle with rounded edges represent in a data flow diagram?

In a data flow diagram, a circle or rectangle with rounded edges is used to represent a process. This symbol indicates an action or transformation that data undergoes within the system. In this context, a process takes inputs, which could be data or information from external entities or data stores, and produces outputs, often transforming the data in some way.

Processes are essential components of data flow diagrams because they help to illustrate how data flows through the system, defining the activities that manage or manipulate that data. By identifying procedures, a developer or analyst can better understand the system's functionality and workflow.

Other elements in a data flow diagram are represented with different shapes: external entities are typically depicted as rectangles, data stores may be shown as open-ended rectangles, and data flows are represented by arrows. Understanding these symbols helps in interpreting the flow of information and the relationships within a system accurately.