What type of diagram is used to represent the physical data flow within a system?

The Physical Data Flow Diagram is specifically designed to illustrate the flow of data within a system, highlighting how data moves between different processes, data stores, and external entities. It provides a visual representation of how data enters, exits, and is transformed during its journey through the system. This diagram emphasizes the physical aspects of data flows, detailing how actual data is handled in real-time operations.

In contrast, the other types of diagrams serve different purposes. For instance, an Entity Relationship Diagram focuses on the logical relationships between data entities rather than the physical flow of data. A Use Case Diagram illustrates the interactions between users (actors) and the system, showcasing what the system should accomplish from an external viewpoint, rather than detailing data flows. Meanwhile, a Data Structure Diagram provides an overview of how data is organized, typically representing the data model rather than its physical flow within processes. Each of these diagrams plays a crucial role in different aspects of system design and analysis but does not specifically map the physical data movements like the Physical Data Flow Diagram does.