We study containment and equivalence of (unions of) conjunctive queries on relations annotated with elements of a commutative semiring. Such relations and the semantics of positiv...
We study the problem of querying data sources that accept only a limited set of queries, such as sources accessible by Web services which can implement very large (potentially inf...
The class of unions of conjunctive queries (UCQ) has been shown to be particularly well-behaved for data exchange; its certain answers can be computed in polynomial time (in terms...
Query folding refers to the activity of determining if and how a query can be answered using a given set of resources, which might be materialized views, cached results of previou...
A mediator is a domain-speci c tool to support uniform access to multiple heterogeneous information sources and to abstract and combine data from different but related databases t...
Jacques Calmet, Sebastian Jekutsch, Joachim Sch&uu...
We study the problem of auditing a batch of SQL queries: Given a forbidden view of a database that should have been kept confidential, a batch of queries that were posed over this ...
A common technique for processing conjunctive queries is to first match each predicate separately using an index lookup, and then compute the intersection of the resulting rowid li...
Robert Krauthgamer, Aranyak Mehta, Vijayshankar Ra...