Calì, Andrea and Martinenghi, D. (2010) Querying incomplete data over extended ER schemata. Theory and Practice of Logic Programming 10 (S03), pp. 291-329. ISSN 1471-0684.
Abstract
Since Chen's Entity-Relationship (ER) model, conceptual modeling has been playing a fundamental role in relational data design. In this paper we consider an extended ER (EER) model enriched with cardinality constraints, disjointness assertions, and is a relations among both entities and relationships. In this setting, we consider the case of incomplete data, which is likely to occur, for instance, when data from different sources are integrated. In such a context, we address the problem of providing correct answers to conjunctive queries by reasoning on the schema. Based on previous results about decidability of the problem, we provide a query answering algorithm that performs rewriting of the initial query into a recursive Datalog query encoding the information about the schema. We finally show extensions to more general settings.
Metadata
Item Type: | Article |
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Keyword(s) / Subject(s): | Extended ER model, dependencies, chase, incomplete data |
School: | Birkbeck Faculties and Schools > Faculty of Science > School of Computing and Mathematical Sciences |
Research Centres and Institutes: | Birkbeck Knowledge Lab |
Depositing User: | Sarah Hall |
Date Deposited: | 10 May 2013 14:12 |
Last Modified: | 09 Aug 2023 12:33 |
URI: | https://eprints.bbk.ac.uk/id/eprint/6690 |
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