Applying Constraint Logic Programming to SQL Semantic Analysis

Abstract

This paper proposes the use of Constraint Logic Programming (CLP) to model SQL queries in a data-independent abstract layer by focusing on some semantic properties for signalling possible errors in such queries. First, we define a translation from SQL to Datalog, and from Datalog to CLP, so that solving this CLP program will give information about inconsistency, tautology, and possible simplifications. We use different constraint domains which are mapped to SQL types, and propose them to cooperate for improving accuracy. Our approach leverages a deductive system that includes SQL and Datalog, and we present an implementation in this system which is currently being tested in classroom, showing its advantages and differences with respect to other approaches, as well as some performance data.

Improving Database Learning with an Automatic Judge

“…DES is a deductive database system that supports many formats and query methods: Datalog, Relational Algebra, Tuple Relational Calculus, Domain Relational Calculus, and SQL. When handling a query, DES performs a set of complex analyses on the code that can detect several semantic errors [10], e.g. unnecessary joins, inconsistent or tautological conditions, or unnecessary subqueries.…”