MANY-SORTED 1ST-ORDER LOGIC DATABASE LANGUAGE

Abstract

A database languages based on Many-Sorted First-Order Logic (MSFOL) have many, advantages over one based on One-Sorted First-Order Logic (OSFOL). The advantages includes ease-of-expressiveness, efficiency, and the abstraction mechanism. Many database researchers have used OSFOL to view the Relational Data Model (RDM); however, no RDM has been modelled by MSFOL. This paper first gives a formal definition for MSFOL and then its advantages of expressiveness and of abstraction are illustrated. Two reduction algorithms which can transform an MSFOL-based language into/from an OSFOL-based language are given. The semantic equivalence between languages based on MSFOL and Typed OSFOL is also proved. Recent extensions of RDMs require aggregation, classification, and generalisation/specialisation mechanisms which MSFOL-based languages can provide, but OSFOL-based languages cannot.