204 search results - page 6 / 41 » Containment of Conjunctive Queries with Negation: Algorithms... |
PODS
2003
ACM
14 years 7 months ago
2003
ACM
In this paper we study the following problem. Given a database and a set of queries, we want to find, in advance, a set of views that can compute the answers to the queries, such ...
JCSS
2008
13 years 7 months ago
2008
We give a quadratic algorithm for the following structure identification problem: given a Boolean relation R and a finite set S of Boolean relations, can the relation R be express...
EDBT
2006
ACM
14 years 7 months ago
2006
ACM
Current methods for selectivity estimation fall into two broad categories, synopsis-based and sampling-based. Synopsis-based methods, such as histograms, incur minimal overhead at ...
ICASSP
2011
IEEE
12 years 11 months ago
2011
IEEE
1 Query-by-example information retrieval provides users a flexible but efficient way to accurately describe their information needs. The query exemplars are usually long and in th...
VLDB
1997
ACM
13 years 12 months ago
1997
ACM
Efficient user-adaptable similarity search more and more increases in its importance for multimedia and spatial database systems. As a general similarity model for multi-dimension...