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

TL;DR

This paper introduces the triangularly-guarded class of TGDs, expanding the landscape of decidable classes for conjunctive query answering and unifying several existing classes under a single framework.

Contribution

The paper defines a new class of TGDs called triangularly-guarded, proving its decidability and finite controllability, and demonstrating it encompasses multiple existing decidable classes.

Findings

Triangularly-guarded TGDs ensure decidable conjunctive query answering.

This class strictly contains weak-acyclic, guarded, sticky, and shy TGDs.

The class provides a unified framework for several known decidable TGD classes.

Abstract

In this paper we introduce a new class of tuple-generating dependencies (TGDs) called triangularly-guarded (TG) TGDs. We show that conjunctive query answering under this new class of TGDs is decidable since this new class of TGDs also satisfies the finite controllability (FC) property. We further show that this new class strictly contains some other decidable classes such as weak-acyclic, guarded, sticky and shy. In this sense, the class TG provides a unified representation of all these aforementioned classes of TGDs.