A New Decidable Class of Tuple Generating Dependencies: The Triangularly-Guarded Class
This work addresses a foundational problem in database theory and logic for researchers and practitioners dealing with data dependencies, providing a unified framework for decidable query answering, though it appears incremental as it builds upon existing classes.
The paper tackles the problem of decidability in conjunctive query answering by introducing triangularly-guarded tuple-generating dependencies (TGDs), showing that query answering under this class is decidable and that it strictly contains several other known decidable classes like weak-acyclic, guarded, sticky, and shy.
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.