On Practical Physical Design

Abstract

We now consider how our plan language together with basic data structures can be composed in various ways to capture more sophisticated data structures and physical design artifacts that are commonly deployed with relational database technology. We investigate how pointers, hashing, user-defined functions, two-level store, and so on, can be accommodated without any need to introduce additional plan operators. Thus, one obtains a practical physical design by:

• 1. adding new predicate symbols and access paths, and

• 2. adding new constraints

to the signature and to the theory of a logical design. We illustrate the approach using an extension of the Option i design for ACME’s payroll system introduced and used in Chapters 2 and 3. This extended design adds two additional predicate symbols to the logical signature S_L of payroll to accommodate information about how employees relate to departments.