492 search results - page 56 / 99 » Computing aggregations in database query languages |
SIGCSE
2005
ACM
15 years 6 months ago
2005
ACM
Universities are increasingly offering courses online. Feedback, assessment, and guidance are important features of this online courseware. Together, in the absence of a human tut...
121
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FOCS
1998
IEEE
15 years 4 months ago
1998
IEEE
This paper deals with the evaluation of acyclic Boolean conjunctive queries in relational databases. By well-known results of Yannakakis [1981], this problem is solvable in polynom...
GIS
2010
ACM
14 years 11 months ago
2010
ACM
This paper proposes an efficient, decentralized algorithm for determining the topological relationship between two regions monitored by a geosensor network. Many centralized algo...
101
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EDBT
2000
ACM
15 years 4 months ago
2000
ACM
OLAP applications use precomputation of aggregate data to improve query response time. While this problem has been well-studied in the recent database literature, to our knowledge ...
DOOD
1995
Springer
15 years 4 months ago
1995
Springer
Wrappers provide access to heterogeneous information sources by converting application queries into source speci c queries or commands. In this paper we present a wrapper implemen...