What Do You Know About Logical Data Models?

The conceptual or logical model is the heart of the heart. It supports all the external views and is, in turn, supported by the internal model. However the internal model is merely the physical implementation of the conceptual model. The conceptual model should be a complete and accurate representation of the workings of the organization in its environment. If that is not the case, some information about the organization Is missing or incorrectly represented and eventually some external view will be inadequate if the conceptual model is correct, it should support any external view needed.

The conceptual model should be the most permanent part, of the database architecture. External views can and should be changed. The internal model should change when new devices or new techniques for representing data and improving performance are developed. However, the conceptual model represents the permanent structure of the data resource of the organization. It should require changes only when the actual workings of the organization or the environment change. Developing the logical model is the most challenging, interesting and rewarding part of database design. During the logical design process, there may be many errors and several false starts.