25 search results - page 1 / 5 » Equivalence and minimization of conjunctive queries under co... |
ICDT
2012
ACM
11 years 7 months ago
2012
ACM
The problems of query containment, equivalence, and minimization are recognized as very important in the context of query processing, specifically of query optimization. In their...
AMW
2011
12 years 8 months ago
2011
Abstract. We consider the problem of checking equivalence of conjunctive queries with inequalities under bag (multiset) semantics. The problem is known to be decidable in pspace an...
PODS
2009
ACM
14 years 5 months ago
2009
ACM
We consider the problem of deciding query equivalence for a conjunctive language in which queries output complex objects composed from a mixture of nested, unordered collection ty...
EDBT
2004
ACM
14 years 5 months ago
2004
ACM
We study the problem of answering queries over sources with limited access patterns. The problem is to decide whether a given query Q is feasible, i.e., equivalent to an executable...
PODS
2006
ACM
14 years 5 months ago
2006
ACM
The query equivalence problem has been studied extensively for set-semantics and, more recently, for bag-set semantics. However, SQL queries often combine set and bag-set semantic...