Formalization of data base models

Abstract

We present abstract, Denotational Semantics models of File Systems and Data Base Languages. The techniques of constructive — as opposed to algebraic — semantics definitions of software, as well as the notation of the specification language, is introduced through a variety of examples of simple file systems. Then these principles of software abstractions are applied to the semantics analysis of both Relational- & Network Data Base Models (i.e. Languages). From the former we illustrate both the relational algebra- and the predicate caluculus- based query languages. Within the Network Model we formalize the notion of Bachman-, i.e. Data Structure-, Diagrams, and the data manipulation language commands applicable to such CODASYL/DBTG-like data models.

The triple aims of the paper are: to teach formalization methods; to advocate the use of abstract models in the Data Base (research) area; and to present the result of some such semantics analysis efforts — hoping thereby to shed light on properties of e.g. CODASYL/DBTG proposals.