Query Extensions and Incremental Query Rewriting for OWL 2 QL Ontologies

Query Rewriting Under Query Extensions for OWL 2 QL Ontologies

Conjunctive query answering is a key reasoning service for many ontology-based applications. With the advent of lightweight ontology languages, such as OWL 2 QL, several query answering systems have been proposed which compute the so called UCQ rewriting of a given query. It is often the case in realistic scenarios, that users refine their original queries, by e.g., extending them with new cons...

Incremental Query Rewriting for OWL 2 QL

Optimized Query Rewriting in OWL 2 QL

The OWL 2 QL profile has been designed to facilitate query answering via query rewriting. This paper presents an optimized query rewriting algorithm which takes advantage of the special characteristics of the query rewriting problem via first-order resolution in OWL 2 QL and computes efficiently the set of the non redundant rewritings of a user query, by avoiding blind and redundant inferences,...

Schema-Agnostic Query Rewriting for OWL QL

Ontology-based query answering (OBQA) has long been an important topic in applied and foundational research, and in particular in the area of description logics (DLs). Query answering has been studied for every major DL, but the most prominent use of DLs in query answering is based on the DLs of the DL-Lite family. In particular, these have widely been used in ontology-based data access (OBDA),...

Goal-oriented Query Rewriting for OWL 2 QL

We present an optimized query rewriting algorithm for OWL 2 QL that computes the rewriting set of a user query by avoiding unnecessary inferences and extended clause subsumption checks. The evaluation shows a significant performance improvement in comparison to other similar approaches. Alternatively, instead of a rewriting set, the algorithm can produce an equivalent non-recursive datalog prog...