Logical data modeling depicts the organization of data and i

Logical data modeling depicts the organization of data and its interrelationships without concern for physical storage and representation. Why is it useful to develop logical models of data? What is the relationship between the data stores of a DFD and the logical data model of some/all of the systems under discussion?

Solution

Logical data modeling depicts the organization of data and its interrelationships without concern for physical storage and representation. Is it useful to develop logical models of data because

Relationship between the data stores of DFD and logical data model:

While any data flow diagram maps out the flow of information for a process or system, the logical diagram provides the “what” and the physical provides the “how.” They are two different perspectives on the same data flow, each designed to visualize and improve the system.

The logical DFD describes the business events that take place and the data required for each event. It provides a solid basis for the physical DFD, which depicts how the data system will work, such as the hardware, software, paper files and people involved

  Another benefit of logical DFDs is that they tend to be more easily understandable to non-technical people.

Data flowcharts can range from simple process overviews, to in-depth, multi-level DFDs that dig progressively deeper into how the data is handled.

They can be used to analyze an existing system or model a new one. They used defined systems of symbols to depict the four components: external entities, processes, data stores and data flow.