569 search results - page 73 / 114 » acm 1995 |
VLDB
1995
ACM
13 years 11 months ago
1995
ACM
In this paper we introduce generalized projections (GPs), an extension of duplicateeliminating projections, that capture aggregations, groupbys, duplicate-eliminating projections ...
VLDB
1995
ACM
13 years 11 months ago
1995
ACM
We provide several new sampling-based estimators of the number of distinct values of an attribute in a relation. We compare these new estimators to estimators from the database an...
VLDB
1995
ACM
13 years 11 months ago
1995
ACM
Traditionally, optimizers are “programmed” to optimize queries following a set of buildin procedures. However, optimizers should be robust to its changing environment to gener...
SIGMOD
2008
ACM
13 years 7 months ago
2008
ACM
James Nicholas Gray's understanding and experimentation gave him a special perspective. From 1995 his commitment was building indefinitely scalable tools by working on really...
ACM
1995
13 years 11 months ago
1995
We study properties of rough sets, that is, approximations to sets of records in a database or, more formally, to subsets of the universe of an information system. A rough set is a...