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» An optimization for query answering on ALC database
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EDBT
2004
ACM
155views Database» more  EDBT 2004»
14 years 7 months ago
Processing Unions of Conjunctive Queries with Negation under Limited Access Patterns
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...
Alan Nash, Bertram Ludäscher
ICDT
2003
ACM
139views Database» more  ICDT 2003»
14 years 20 days ago
New Rewritings and Optimizations for Regular Path Queries
All the languages for querying semistructured data and the web use as an integral part regular expressions. Based on practical observations, finding the paths that satisfy those r...
Gösta Grahne, Alex Thomo
DLOG
2008
13 years 9 months ago
Taming the Infinite Chase: Query Answering under Expressive Relational Constraints
Answering queries posed over knowledge bases is a central problem in knowledge representation and database theory. In databases, query containment is one of the important query op...
Andrea Calì, Georg Gottlob, Michael Kifer
ICDE
2008
IEEE
336views Database» more  ICDE 2008»
14 years 8 months ago
Dominant Graph: An Efficient Indexing Structure to Answer Top-K Queries
Given a record set D and a query score function F, a top-k query returns k records from D, whose values of function F on their attributes are the highest. In this paper, we investi...
Lei Zou, Lei Chen 0002
KDD
1994
ACM
98views Data Mining» more  KDD 1994»
13 years 11 months ago
Rule Induction for Semantic Query Optimization
Semantic query optimization can dramatically speed up database query answering by knowledge intensive reformulation. But the problem of how to learn required semantic rules has no...
Chun-Nan Hsu, Craig A. Knoblock