Abstract Information systems have to deal with an increasing amount of data that is
heterogeneous, unstructured, or incomplete. In order to align and complete data, systems …

In this paper, we introduce a family of expressive extensions of Datalog, called Datalog+/-,
as a new paradigm for query answering over ontologies. The Datalog+/-family admits …

The chase algorithm is a fundamental tool for query evaluation and for testing query
containment under tuple-generating dependencies (TGDs) and equality-generating …

In this paper we present MASTRO, a Java tool for ontology-based data access (OBDA)
developed at Sapienza Università di Roma and at the Free University of Bozen-Bolzano …

Ontology-based data access is concerned with querying incomplete data sources in the
presence of domain-specific knowledge provided by an ontology. A central notion in this …

In this paper we study data complexity of answering conjunctive queries over description
logic (DL) knowledge bases constituted by a TBox and an ABox. In particular, we are …

Ontology reasoning finds a relevant application in the so-called ontology-based data
access, where a classical extensional database (EDB) is enhanced by an ontology, in the …

We present the architecture and technologies underpinning the OBDA system Ontop and
taking full advantage of storing data in relational databases. We discuss the theoretical …

Abstract An Introduction to Ontology Engineering is a free online textbook that provides an
overview of ontology engineering, including logics and automated reasoning, methods and …

The use of ontologies for accessing data is one of the most exciting new applications of
description logics in databases and other information systems. A realistic way of realising …