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Computing Possible and Certain Answers ...
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Document type :
Article dans une revue scientifique
DOI :
10.1016/j.tcs.2019.05.013
Permalink :
http://hdl.handle.net/20.500.12210/74900
Title :
Computing Possible and Certain Answers over Order-Incomplete Data
Author(s) :
Amarilli, Antoine [Auteur]
Data, Intelligence and Graphs [DIG]
Ba, Mouhamadou Lamine [Auteur]

Deutch, Daniel [Auteur]

Senellart, Pierre [Auteur]
Data, Intelligence and Graphs [DIG]
Value from Data [VALDA ]
Journal title :
Theoretical Computer Science
Pages :
42-76
Publisher :
Elsevier
Publication date :
2019
ISSN :
1879-2294
English keyword(s) :
Uncertain data
Partial order
Certain answer
Possible answer
HAL domain(s) :
Informatique [cs]/Base de données [cs.DB]
Informatique [cs]/Web
English abstract : [en]
This paper studies the complexity of query evaluation for databases whose relations are partially ordered; the problem commonly arises when combining or transforming ordered data from multiple sources. We focus on queries ...
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This paper studies the complexity of query evaluation for databases whose relations are partially ordered; the problem commonly arises when combining or transforming ordered data from multiple sources. We focus on queries in a useful fragment of SQL, namely positive relational algebra with aggregates, whose bag semantics we extend to the partially ordered setting. Our semantics leads to the study of two main computational problems: the possibility and certainty of query answers. We show that these problems are respectively NP-complete and coNP-complete, but identify tractable cases depending on the query operators or input partial orders. We further introduce a duplicate elimination operator and study its effect on the complexity results.Show less >
Language :
Anglais
Peer reviewed article :
Oui
Audience :
Internationale
Popular science :
Non
Collections :
  • Centre de Recherche en Informatique, Signal et Automatique de Lille (CRIStAL) - UMR 9189
Source :
Harvested from HAL
Submission date :
2022-06-15T02:26:45Z
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  • http://arxiv.org/pdf/1801.06396
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