High Level Expression of Semantic Integrity Specifications in a Relational Data Base System

Abstract

The "semantic integrity" of a data base is said to be violated when the data base ceases to represent a legitimate configuration of the application environment it is intended to model. In the context of the relational data model, it is possible to identify multiple levels of semantic integrity information: (1) the description of the domains of the data base, as abstract sets of atomic data values (domain definition), (2) the specification of the fundamental structure of the data (relation structure specification), (3) the definition of the abstract operations which are meaningful in terms of the application environment (structured operations), and (4) the expression of additional semantic information not contained in the structure of the relations nor in the identities of their underlying domains (relation constraints).