126 search results - page 16 / 26 » The Complexity of Acyclic Conjunctive Queries |
DEXA
1994
Springer
13 years 11 months ago
1994
Springer
Even if high-level query languages are used, query formulation may cause problems. This is notably so in case of large and complex application domains. Typical examples of these ki...
SIGMOD
2006
ACM
14 years 7 months ago
2006
ACM
We present and analyze an algorithm for equivalent rewriting of XQuery queries using XQuery views, which is complete for a large class of XQueries featuring nested FLWR blocks, XM...
ICDE
2006
IEEE
14 years 9 months ago
2006
IEEE
We present MiniCount, the first efficient sound and complete algorithm for finding maximally contained rewritings of conjunctive queries with count, using conjunctive views with c...
AAAI
2012
11 years 10 months ago
2012
We tackle the problem of defining a well-founded semantics (WFS) for Datalog rules with existentially quantified variables in their heads and negations in their bodies. In partic...
PODS
2004
ACM
14 years 7 months ago
2004
ACM
We study the problem of answering queries over sources with limited access patterns. Given a first-order query Q, the problem is to decide whether there is an equivalent query whi...