Data Modeling


Data modeling is the art and science of arranging the structure and relationship of data to be stored in such a way as to optimize certain characteristics of the use of the data. In the early days of data processing, one of the main goals of data modeling was to optimize the storage of data. Later it became optimizing the access of the data. Relational theory brought with it a style of data modeling that emphasized integrity management and ensuring consistency in the presence of updates.

Object-oriented design is a form of data modeling, although practitioners typically don't think of it that way. They don't think of it that way partially because they still often store their data in relational databases and because they concentrate on modeling the behavior of the system, with the data being secondary. However, data modeling is going on in any object-oriented system. It is optimized either for reuse (classes inherit from other classes in a way that allows them to reuse, as much as possible, the shared attributes in a parent class) or for polymorphism (any of a number of different objects can be treated similarly, but they still preserve their difference where appropriate).

Data modeling also proceeds from high-level abstract models, through logical models, to physical models, and on to implementation. At each level, constraints about the target implementation are introduced. What should happen, but rarely does, is that the conceptual and logical models should be preserved and cross-referenced to their physical counterparts. System changes should be introduced at the conceptual level and rippled through, maintaining the correlations all the way through. However, this is rarely done. Once a system is implemented, maintainers know that they will be making their changes to the implemented model, and they see little benefit in maintaining the upper levels.

This is unfortunate, because many of the problems of systems integration and intercompany commerce can only be addressed at the higher levels.

Semantic modeling is a type of conceptual modeling that focuses on the meaning of the information. Further, it focuses on describing the meaning in such a way that similarities are uncovered and there is much more opportunity for shared functionality.




Semantics in Business Systems(c) The Savvy Manager's Guide
Semantics in Business Systems: The Savvy Managers Guide (The Savvy Managers Guides)
ISBN: 1558609172
EAN: 2147483647
Year: 2005
Pages: 184
Authors: Dave McComb

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