Introduction to Physical Schema Definition

Abstract

The challenge for physical database designers is to convert the logical specifications created during requirements definition into something that is usable by the organization. This can be a trying task because, unlike the logical data modeler, the physical database designer must adjudicate competing requests for resources. For example, do you tune the database to rapidly access online customer information and in the process penalize batch order processing, or do you favor order processing and, as a result, decrease the performance of customer service? For some, this dilemma is a no-win proposition—no matter what you do, you will displease someone. However, if you recognize that, beyond applying the fundamentals of physical database design, database designers spend most of their time juggling the trade-offs of aiding one user’s data access at the cost of another’s, you realize that the methods of measuring resource usage and arriving at the right balance for the organization is what physical database design is all about.