
Chapter 3
Physical Database Design
Relational database systems provide physical data independence. That is,
no matter which index configuration constitutes the physical design of the
database, queries always return the same results. Of course, the performance
of evaluating queries over different physical designs (i.e., different index con-
figurations) can vary significantly. For that reason, together with the capabili-
ties of the execution engine and query optimizer (discussed in Chapter 2), the
physical design of a database determines how efficiently a query is executed.
There is no such a thing as the optimal physical design for a database,
unless we state ...