A New Decidable Class of Tuple Generating Dependencies: The Triangularly-Guarded Class

TL;DR

This paper introduces the triangularly-guarded class of TGDs, a new decidable class that encompasses several existing classes, enabling decidable conjunctive query answering under more expressive dependencies.

Contribution

The paper defines the triangularly-guarded class of TGDs and proves its decidability, unifying multiple existing decidable classes into a single framework.

Findings

Decidable conjunctive query answering under triangularly-guarded TGDs.

Triangularly-guarded class strictly contains weak-acyclic, guarded, sticky, and shy classes.

Provides a unified framework for various decidable TGD classes.

Abstract

In this paper we introduce a new class of tuple-generating dependencies (TGDs) called triangularly-guarded TGDs, which are TGDs with certain restrictions on the atomic derivation track embedded in the underlying rule set. We show that conjunctive query answering under this new class of TGDs is decidable. We further show that this new class strictly contains some other decidable classes such as weak-acyclic, guarded, sticky and shy, which, to the best of our knowledge, provides a unified representation of all these aforementioned classes.