The bag semantics of ontology−based data access
The bag semantics of ontology−based data access
Ontology-based data access (OBDA) is a popular approach for integrating and querying multiple data sources by means of a shared ontology. The ontology is linked to the sources using mappings, which assign views over the data to ontology predicates. Motivated by the need for OBDA systems supporting database-style aggregate queries, we propose a bag semantics for OBDA, where duplicate tuples in the views defined by the mappings are retained, as is the case in standard databases. We show that bag semantics makes conjunctive query answering in OBDA CONP-hard in data complexity. To regain tractability, we consider a rather general class of queries and show its rewritability to a generalisation of the relational calculus to bags.
1224-1230
International Joint Conferences on Artificial Intelligence
Nikolaou, Charalampos
8f136351-0f3f-479c-b709-311be8138b03
Kostylev, Egor V.
68747f03-563d-4ae1-9471-e7561770dae4
Konstantinidis, Georgios
f174fb99-8434-4485-a7e4-bee0fef39b42
Kaminski, Mark
ab75eafc-19b9-426a-8006-3cc47c8ea853
Grau, Bernardo Cuenca
dafe1057-dd00-4f38-aaed-79605ce86a78
Horrocks, Ian
b8e97f51-6af4-4351-a05c-10b23413652f
August 2017
Nikolaou, Charalampos
8f136351-0f3f-479c-b709-311be8138b03
Kostylev, Egor V.
68747f03-563d-4ae1-9471-e7561770dae4
Konstantinidis, Georgios
f174fb99-8434-4485-a7e4-bee0fef39b42
Kaminski, Mark
ab75eafc-19b9-426a-8006-3cc47c8ea853
Grau, Bernardo Cuenca
dafe1057-dd00-4f38-aaed-79605ce86a78
Horrocks, Ian
b8e97f51-6af4-4351-a05c-10b23413652f
Nikolaou, Charalampos, Kostylev, Egor V., Konstantinidis, Georgios, Kaminski, Mark, Grau, Bernardo Cuenca and Horrocks, Ian
(2017)
The bag semantics of ontology−based data access.
In Proceedings of Twenty−Sixth International Joint Conference on Artificial Intelligence.
International Joint Conferences on Artificial Intelligence.
.
(doi:10.24963/ijcai.2017/170).
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Conference or Workshop Item
(Paper)
Abstract
Ontology-based data access (OBDA) is a popular approach for integrating and querying multiple data sources by means of a shared ontology. The ontology is linked to the sources using mappings, which assign views over the data to ontology predicates. Motivated by the need for OBDA systems supporting database-style aggregate queries, we propose a bag semantics for OBDA, where duplicate tuples in the views defined by the mappings are retained, as is the case in standard databases. We show that bag semantics makes conjunctive query answering in OBDA CONP-hard in data complexity. To regain tractability, we consider a rather general class of queries and show its rewritability to a generalisation of the relational calculus to bags.
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Accepted/In Press date: 1 August 2017
e-pub ahead of print date: August 2017
Published date: August 2017
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Local EPrints ID: 423212
URI: http://eprints.soton.ac.uk/id/eprint/423212
PURE UUID: be80d0cc-62b3-4ba0-ad75-8bc2615b6bc6
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Date deposited: 19 Sep 2018 16:30
Last modified: 15 Mar 2024 21:27
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Contributors
Author:
Charalampos Nikolaou
Author:
Egor V. Kostylev
Author:
Georgios Konstantinidis
Author:
Mark Kaminski
Author:
Bernardo Cuenca Grau
Author:
Ian Horrocks
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