357 search results - page 1 / 72 » An Algebraic Approach to the Complexity of Generalized Conju... |
SAT
2004
Springer
13 years 10 months ago
2004
Springer
Kolaitis and Vardi pointed out that constraint satisfaction and conjunctive query containment are essentially the same problem. We study the Boolean conjunctive queries under a mor...
PODS
2010
ACM
13 years 10 months ago
2010
ACM
We investigate a higher-order query language that embeds operators of the positive relational algebra within the simply-typed λ-calculus. Our language allows one to succinctly de...
DBPL
2007
Springer
13 years 11 months ago
2007
Springer
Annotated relational databases can be queried either by simply making the annotations explicitly available along the ordinary data, or by adapting the standard query operators so ...
EDBT
2002
ACM
14 years 5 months ago
2002
ACM
The problem of finding contained rewritings of queries using views is of great importance in mediated data integration systems. In this paper, we first present a general approach f...
FOCS
1998
IEEE
13 years 9 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...