RELATIONSHIP RELATIONS AND NATURAL QUANTIFICATION IN RELATIONAL DATABASES

Abstract

An alternative to the conventional method of constructing retrieval expressions for relational databases is proposed. This alternative uses precise definitions of relationships between relations, in the form of relationship relations, as well as quantification of subsets of a relation that are related to any tuple in the database. The relationship relation is used to precisely define how a subset of a relation is related to a tuple. This approach permits not only the existential and universal quantifiers, but also the large number of natural quantifiers that exist. Resulting set theoretic expressions, and expressions in relational languages based on this technique, usually mirror the corresponding natural language statement.