31 search results - page 2 / 7 » Some Algorithmic Improvements for the Containment Problem of... |
PODS
2010
ACM
13 years 10 months ago
2010
ACM
Both semantic and type-based query optimization rely on the idea that queries often exhibit non-trivial rewritings if the state space of the database is restricted. Despite their ...
PODS
2004
ACM
14 years 5 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...
AAAI
2010
13 years 6 months ago
2010
Conjunctive query answering is a key reasoning service for many ontology-based applications. In order to improve scalability, many Semantic Web query answering systems give up com...
SIGMOD
2006
ACM
14 years 5 months ago
2006
ACM
We study the problem of finding efficient equivalent viewbased rewritings of relational queries, focusing on query optimization using materialized views under the assumption that ...
STOC
2009
ACM
14 years 5 months ago
2009
ACM
This paper studies constant-time approximation algorithms for problems on degree-bounded graphs. Let n and d be the number of vertices and the degree bound, respectively. This pap...