DeepAI AI Chat
Log In Sign Up

Relaxing and Restraining Queries for OBDA

by   Medina Andreşel, et al.

In ontology-based data access (OBDA), ontologies have been successfully employed for querying possibly unstructured and incomplete data. In this paper, we advocate using ontologies not only to formulate queries and compute their answers, but also for modifying queries by relaxing or restraining them, so that they can retrieve either more or less answers over a given dataset. Towards this goal, we first illustrate that some domain knowledge that could be naturally leveraged in OBDA can be expressed using complex role inclusions (CRI). Queries over ontologies with CRI are not first-order (FO) rewritable in general. We propose an extension of DL-Lite with CRI, and show that conjunctive queries over ontologies in this extension are FO rewritable. Our main contribution is a set of rules to relax and restrain conjunctive queries (CQs). Firstly, we define rules that use the ontology to produce CQs that are relaxations/restrictions over any dataset. Secondly, we introduce a set of data-driven rules, that leverage patterns in the current dataset, to obtain more fine-grained relaxations and restrictions.


Computing Datalog Rewritings beyond Horn Ontologies

Rewriting-based approaches for answering queries over an OWL 2 DL ontolo...

Ontology-based industrial data management platform

Relational and noSQL storages are developed for the fast processing of t...

The Logical Difference for the Lightweight Description Logic EL

We study a logic-based approach to versioning of ontologies. Under this ...

Finding Good Proofs for Answers to Conjunctive Queries Mediated by Lightweight Ontologies (Technical Report)

In ontology-mediated query answering, access to incomplete data sources ...

Enhancements of linked data expressiveness for ontologies

The semantic web has received many contributions of researchers as ontol...

Query Inseparability for ALC Ontologies

We investigate the problem whether two ALC ontologies are indistinguisha...

Semantic-based Anomalous Pattern Discovery in Moving Object Trajectories

In this work, we investigate a novel semantic approach for pattern disco...