What is the Difference Between Physical DFD and Logical DFD?

The main difference between a physical Data Flow Diagram (DFD) and a logical DFD lies in their focus and level of abstraction. Here are the key differences:

• Logical DFD: This type of DFD focuses on the business and how the business operates. It describes the business events that take place and the data required and produced by each event. Logical DFDs provide a user-centric, abstract view during early phases of system development, ensuring that the system's design aligns with user requirements.
• Physical DFD: This type of DFD shows how the system will be implemented, including the hardware, software, files, and people involved. Physical DFDs dive into the technical aspects of system implementation, detailing how the logical components identified in the logical DFD are realized in terms of specific technologies and resources.

In summary, logical DFDs concentrate on the high-level abstraction of processes and data, while physical DFDs focus on the detailed implementation of the system using specific technologies and resources. Both types of DFDs play vital roles at different stages of a system's development lifecycle, with logical DFDs being used during the early phases and physical DFDs being utilized during the detailed system design phase.

Comparative Table: Physical DFD vs Logical DFD

The main difference between a physical and logical data flow diagram (DFD) lies in the level of detail and the focus of the diagram. Here is a comparison table:

A logical DFD focuses on the business activities and processes, showing how data flows through a system without going into the implementation details. On the other hand, a physical DFD looks at how the system will be implemented, including the hardware, software, files, and people involved. The logical DFD provides a foundation for creating a physical DFD, which in turn helps in designing and implementing the actual system.