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ICDT
2012
ACM
226views Database» more  ICDT 2012»
7 years 1 months ago
Factorised representations of query results: size bounds and readability
We introduce a representation system for relational data based on algebraic factorisation using distributivity of product over union and commutativity of product and union. We giv...
Dan Olteanu, Jakub Zavodny
PODS
2012
ACM
253views Database» more  PODS 2012»
7 years 1 months ago
Local transformations and conjunctive-query equivalence
Over the past several decades, the study of conjunctive queries has occupied a central place in the theory and practice of database systems. In recent years, conjunctive queries h...
Ronald Fagin, Phokion G. Kolaitis
PODS
2012
ACM
297views Database» more  PODS 2012»
7 years 1 months ago
Query-based data pricing
Data is increasingly being bought and sold online, and Webbased marketplace services have emerged to facilitate these activities. However, current mechanisms for pricing data are ...
Paraschos Koutris, Prasang Upadhyaya, Magdalena Ba...
IS
2012
7 years 6 months ago
View determinacy for preserving selected information in data transformations
When transforming data one often wants certain information in the data source to be preserved, i.e., we identify parts of the source data and require these parts to be transformed...
Wenfei Fan, Floris Geerts, Lixiao Zheng
CIKM
2011
Springer
7 years 11 months ago
Semantic data markets: a flexible environment for knowledge management
We present Nyaya, a system for the management of Semantic-Web data which couples a general-purpose and extensible storage mechanism with efficient ontology reasoning and querying ...
Roberto De Virgilio, Giorgio Orsi, Letizia Tanca, ...
SIGMOD
2011
ACM
202views Database» more  SIGMOD 2011»
8 years 1 months ago
Sensitivity analysis and explanations for robust query evaluation in probabilistic databases
Probabilistic database systems have successfully established themselves as a tool for managing uncertain data. However, much of the research in this area has focused on efficient...
Bhargav Kanagal, Jian Li, Amol Deshpande
DLOG
2011
8 years 2 months ago
On (In)Tractability of OBDA with OWL 2 QL
We show that, although conjunctive queries over OWL 2 QL ontologies are reducible to database queries, no algorithm can construct such a reduction in polynomial time without changi...
Stanislav Kikot, Roman Kontchakov, Michael Zakhary...
EUSFLAT
2009
122views Fuzzy Logic» more  EUSFLAT 2009»
8 years 8 months ago
Semantic Proximity Between Queries and the Empty Answer Problem
This paper proposes an approach aimed at obviating empty answers for a family of conjunctive queries involving Boolean or fuzzy value constraints. Contrary to the approaches based ...
Patrick Bosc, Carmen Brando, Allel HadjAli, H&eacu...
ADBIS
2009
Springer
135views Database» more  ADBIS 2009»
8 years 9 months ago
Systematic Exploration of Efficient Query Plans for Automated Database Restructuring
We consider the problem of selecting views and indexes that minimize the evaluation costs of the important queries under an upper bound on the disk space available for storing the ...
Maxim Kormilitsin, Rada Chirkova, Yahya Fathi, Mat...
RR
2010
Springer
8 years 9 months ago
Redundancy Elimination on RDF Graphs in the Presence of Rules, Constraints, and Queries
Based on practical observations on rule-based inference on RDF data, we study the problem of redundancy elimination on RDF graphs in the presence of rules (in the form of Datalog r...
Reinhard Pichler, Axel Polleres, Sebastian Skritek...
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