The Logic of a Relational Data Manipulation Language

Abstract

A logic for a relational data manipulation language is defined by augmenting a known logic of programs with rules for two new statements: the relational assignment, which assign a relational expression to a relation, and the random tuple selection, which extracts an arbitrary tuple from a relation. The usual operations on relations-retrieve, insert, delete, update-are then defined as special cases of the relational assignment, and the for-each construct scanning a relation tuple by tuple is introduced with the help of the random tuple selection.