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| Content Provider | ACM Digital Library |
|---|---|
| Author | Bienvenu, Meghyn Wolter, Frank Cate, Balder Ten Lutz, Carsten |
| Copyright Year | 2014 |
| Abstract | Ontology-based data access is concerned with querying incomplete data sources in the presence of domain-specific knowledge provided by an ontology. A central notion in this setting is that of an ontology-mediated query, which is a database query coupled with an ontology. In this article, we study several classes of ontology-mediated queries, where the database queries are given as some form of conjunctive query and the ontologies are formulated in description logics or other relevant fragments of first-order logic, such as the guarded fragment and the unary negation fragment. The contributions of the article are threefold. First, we show that popular ontology-mediated query languages have the same expressive power as natural fragments of disjunctive datalog, and we study the relative succinctness of ontology-mediated queries and disjunctive datalog queries. Second, we establish intimate connections between ontology-mediated queries and constraint satisfaction problems (CSPs) and their logical generalization, MMSNP formulas. Third, we exploit these connections to obtain new results regarding: (i) first-order rewritability and datalog rewritability of ontology-mediated queries; (ii) P/NP dichotomies for ontology-mediated queries; and (iii) the query containment problem for ontology-mediated queries. |
| Starting Page | 1 |
| Ending Page | 44 |
| Page Count | 44 |
| File Format | |
| ISSN | 03625915 |
| e-ISSN | 15574644 |
| DOI | 10.1145/2661643 |
| Volume Number | 39 |
| Issue Number | 4 |
| Journal | ACM Transactions on Database Systems (TODS) |
| Language | English |
| Publisher | Association for Computing Machinery (ACM) |
| Publisher Date | 2014-12-30 |
| Publisher Place | New York |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Ontology-based data access Query answering Query rewriting |
| Content Type | Text |
| Resource Type | Article |
| Subject | Information Systems |
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