2063 search results - page 9 / 413 » Containment of Aggregate Queries |
ADBIS
2009
Springer
14 years 2 months ago
2009
Springer
Abstract. We consider the problem of query containment for conjunctive queries with the safe negation property. Some necessary conditions for this problem are given. A part of the ...
DEXAW
1998
IEEE
13 years 11 months ago
1998
IEEE
Materialized views offer opportunities for significant performance gain in query evaluation by providing fast access to pre-computed data. The question of when and how to use a ma...
SEMWEB
2005
Springer
14 years 28 days ago
2005
Springer
Semantic query optimization (SQO) has been proved to be quite useful in various applications (e.g., data integration, graphical query generators, caching, etc.) and has been extens...
DAIS
2009
13 years 5 months ago
2009
Queries are widely used for acquiring data distributed in opportunistically formed mobile networks. However, when queries are executed in such dynamic settings, the returned result...
ICDT
2010
ACM
13 years 9 months ago
2010
ACM
When a query is evaluated under bag semantics, each answer is returned as many times as it has derivations. Bag semantics has long been recognized as important, especially when ag...