25 search results - page 2 / 5 » Size and treewidth bounds for conjunctive queries |
AMW
2011
12 years 11 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...
FOCS
1998
IEEE
13 years 11 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...
ACTA
2007
13 years 7 months ago
2007
Abstract We propose an exact algorithm for counting the models of propositional formulas in conjunctive normal form (CNF). Our algorithm is based on the detection of strong backdoo...
PODS
2003
ACM
14 years 7 months ago
2003
ACM
In this paper we study the following problem. Given a database and a set of queries, we want to find, in advance, a set of views that can compute the answers to the queries, such ...
IJCAI
2007
13 years 8 months ago
2007
Conjunctive queries play an important role as an expressive query language for Description Logics (DLs). Although modern DLs usually provide for transitive roles, conjunctive quer...