The state of the art commercial query optimizers employ cost-based optimization and exploit dynamic programming (DP) to find the optimal query execution plan (QEP) without evalua...
An effective query optimizer finds a query plan that exploits the characteristics of the source data. In data integration, little is known in advance about sources' propertie...
Vertical partitioning is a well-known technique for optimizing query performance in relational databases. An extreme form of this technique, which we call vectorization, is to sto...
Peter Buneman, Byron Choi, Wenfei Fan, Robert Hutc...
Access limitations may occur when querying data sources over the web or heterogeneous data sources presented as relational tables: this happens, for instance, in Data Exchange and ...
Efficiently querying RDF [1] data is being an important factor in applying Semantic Web technologies to real-world applications. In this context, many efforts have been made to st...