What is the difference between logical and physical designs?

The distinction between logical and physical designs is fundamentally rooted in the focus and level of abstraction involved in each phase of the design process.

Logical design is concerned with the abstract representation of the system. It emphasizes the functional requirements, user needs, and the underlying structure of the system without delving into the specific technologies or physical constraints. It’s about how data will be organized, how processes will function, and what needs to be achieved from a user’s perspective, often expressed in terms of data modeling and process flows.

In contrast, physical design takes the logical design and translates it into a concrete implementation. This stage involves decisions about hardware, software, network architecture, and database management systems that will actually support the system. Essentially, physical design is where the nuances of technology come into play and where the system is built according to the parameters set forth in the logical design.

Understanding this difference is crucial for effective systems analysis and design, as it ensures that the system is both conceptually sound and pragmatically feasible. This layered approach allows designers and stakeholders to first agree on what the system should do before getting into how to make it happen physically.