In this paper we focus on the following problem in information management: given a large collection of recorded information and some knowledge of the process that is generating th...
A Data Warehouse DW can be abstractly seen as a set of materialized views de ned over relations that are stored in distributed heterogeneous databases. The selection of views for...
Spyros Ligoudistianos, Timos K. Sellis, Dimitri Th...
The prevalent use of XML highlights the need for a generic, flexible access-control mechanism for XML documents that supports efficient and secure query access, without revealing ...
Estimating the number of distinct values is a wellstudied problem, due to its frequent occurrence in queries and its importance in selecting good query plans. Previous work has sh...
Data warehouses store materialized views over base data from external sources. Clients typically perform complex read-only queries on the views. The views are refreshed periodical...