Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/75200
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Type: | Journal article |
Title: | Tackling polytype queries in inconsistent databases: theory and algorithm |
Author: | Xie, Dong Chen, Xinbo Zhu, Yan |
Citation: | Journal of Software, 2012; 7(8):1861-1866 |
Publisher: | Academy Publisher |
Issue Date: | 2012 |
ISSN: | 1796-217X |
School/Discipline: | School of Computer Science |
Statement of Responsibility: | Dong Xie, Xinbo Chen, Yan Zhu |
Abstract: | To expand query types under a set of integrity constraints for obtaining consistent answers over inconsistent databases, a computational theory is proposed based on first-order logic. According to directed join graphs of queries and their join completeness, computational complexities of CQA are PTIME if query types are key-key, nonkey-key, incomplete key-key with acyclic join. This paper presents several algorithms to tackle a large and practical class of queries, which can obtain the rewritten queries for computing consistent answers. For a rewritable initial query, a consistent identification statement is constructed based on the join graph by recursive computation; and the statement combines with the initial query to construct a new first-order rewritten query for computing consistent answers. To acyclic self-join queries, the recursive rewriting algorithm cannot eliminate inconsistent tuples, so the initial query combines with the statement that eliminates them. |
Keywords: | relational database; inconsistent data; consistent query answer; first-order logic; query rewriting |
Rights: | © 2012 ACADEMY PUBLISHER |
DOI: | 10.4304/jsw.7.8.1861-1866 |
Appears in Collections: | Computer Science publications |
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