Including scalars in a programming language based on the relational algebra

Scalars, arrays, and records, together with associated operations and syntax, have been introduced as special cases of relations into the relational programming system, relix. This permits all of these data types, as well as relations, to be stored persistently. The requirement in most languages that array elements and record fields can be assigned to leads in this case to the general implementation of QT-selectors as l-expressions, with, in particular, systematic interpretations of assignment to projections and selections of relations. The authors discuss the principles and the implementation of this extension to the relational algebra. They take advantage of the very specialized syntax of array access to build a tuned access method, using B-trees and Z-order. The performance results show the advantage of this implementation over the slower implementation required for general QT-selectors