In this paper we investigate the feasibility and efficiency of mapping XML data and access control policies onto relational and native XML databases for storage and querying. We de...
Lazaros Koromilas, George Chinis, Irini Fundulaki,...
Abstract In this article, we present a comprehensive approach for privacy preserving access control based on the notion of purpose. In our model, purpose information associated wit...
Internet search engines have popularized the keywordbased search paradigm. While traditional database management systems offer powerful query languages, they do not allow keyword-...
We rework parts of the classical relational theory when the underlying domain is a structure with some interpreted operations that can be used in queries. We identify parts of the...
Abstract. We study containment of conjunctive queries that are evaluated over databases that may contain tuples with null values. We assume the semantics of SQL for single block qu...