Foundations of Ontology-Based Data Access under Bag Semantics
- Submitting institution
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University of Oxford
- Unit of assessment
- 11 - Computer Science and Informatics
- Output identifier
- 2078
- Type
- D - Journal article
- DOI
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10.1016/j.artint.2019.02.003
- Title of journal
- Artificial Intelligence
- Article number
- -
- First page
- 91
- Volume
- 274
- Issue
- -
- ISSN
- 1872-7921
- Open access status
- Compliant
- Month of publication
- February
- Year of publication
- 2019
- URL
-
-
- Supplementary information
-
-
- Request cross-referral to
- -
- Output has been delayed by COVID-19
- No
- COVID-19 affected output statement
- -
- Forensic science
- No
- Criminology
- No
- Interdisciplinary
- No
- Number of additional authors
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5
- Research group(s)
-
-
- Citation count
- 4
- Proposed double-weighted
- No
- Reserve for an output with double weighting
- No
- Additional information
- The conference version of this paper was in IJCAI�17. Ontology-based data access (OBDA) is a popular approach for integrating and querying multiple data sources by means of a shared ontology. However, the set-based semantics of ontologies is inconsistent with the bag semantics used in databases. This paper examines the issue in detail, proposes an alternative bag semantics for OBDA, and presents a rigorous analysis of its computational properties. It is shown that adopting bag semantics makes conjunctive query answering coNP-hard in data complexity, but that tractability can be restored via minor restrictions on the ontology or query language.
- Author contribution statement
- -
- Non-English
- No
- English abstract
- -