A Framework for a Tool for Physical Database Design

The design of an optimal physical database entails an exponential time complexity. This is the main reason which has shifted the attention of researchers to the problem of determining a good physical database design. Two kinds of approaches have been proposed to nd a good physical design, an optimizer and a knowledge based approach. An optimizer based approach is characterized by generating physical designs on basis of extracted information from the optimizer. The knowledge based approach is characterized by representing the knowledge of experts, not necessarily knowledge with regard to optimizers, into rules. In this paper we will propose a framework of a tool based on a combination of both approaches which can assist in nding a good physical design. In our approach the emphasis lies on the knowledge based aspects such as how to represent knowledge into rules and how to combine diierent rules. Knowledge based approaches for physical design take ad hoc decisions for these subjects. We believe that these kinds of decisions are essential for a knowledge based approach because the generated solutions are determined by the rules and combination of rules. We will present a technique how to model knowledge in a more proper way into rules. This makes it possible to combine rules in a founded way with the Dempster-Shafer theory, nally leading to a good proposal for physical design.