99 search results - page 9 / 20 » On the complexity of division and set joins in the relationa... |
SIGMOD
1996
ACM
14 years 2 days ago
1996
ACM
Magic sets rewriting is a well-known optimization heuristic for complex decision-support queries. There can be many variants of this rewriting even for a single query, which diffe...
ICALP
2007
Springer
14 years 2 months ago
2007
Springer
We present algebraic conditions on constraint languages Γ that ensure the hardness of the constraint satisfaction problem CSP(Γ) for complexity classes L, NL, P, NP and ModpL. Th...
ICDE
2007
IEEE
14 years 9 months ago
2007
IEEE
Algorithms that exploit sort orders are widely used to implement joins, grouping, duplicate elimination and other set operations. Query optimizers traditionally deal with sort ord...
PODS
2006
ACM
14 years 8 months ago
2006
ACM
We study the randomized version of a computation model (introduced in [9, 10]) that restricts random access to external memory and internal memory space. Essentially, this model c...
CP
2000
Springer
13 years 11 months ago
2000
Springer
We are interested in the expressiveness of constraints represented by general first order formulae, with equality as unique relation symbol and function symbols taken from an infi...