Ricerc@Sapienza

In Controlled Query Evaluation (CQE) confidential data are protected through a declarative policy and a (optimal) censor, which guarantees that answers to queries are maximized without disclosing secrets. In this paper we consider CQE over Description Logic ontologies and study query answering over all optimal censors. We establish data complexity of the problem for ontologies specified in DL-LiteR and for variants of the censor language, which is the language used by the censor to enforce the policy.

The Ontology-Based Data Access (OBDA) paradigm aims at providing to the users a unified and shared conceptual view of the domain of interest (ontology), while still enabling the data to be stored in different data sources. Such data are mapped to the ontology through declarative specifications. In this work we consider the ontology expressed in OWL 2 QL, relational sources, the mapping expressed in R2RML, and the user queries expressed in SPARQL.