Volume 7 Number 8 (Aug. 2012)
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JSW 2012 Vol.7(8): 1861-1866 ISSN: 1796-217X
doi: 10.4304/jsw.7.8.1861-1866

Tackling Polytype Queries in Inconsistent Databases: Theory and Algorithm

Dong Xie1, 2, Xinbo Chen3, Yan Zhu3

1Department of Computer Science and Technology, Hunan University of Humanities, Science and Technology, Loudi, 417000, China
2School of Computer Science, The University of Adelaide, SA 5005, Australia
3Department of Electronics and Information Engineering, Loudi Vocational and Technical College, Loudi, 417000, China

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.

Index Terms—relational database, inconsistent data; consistent query answer, first-order logic, query rewriting


Cite: Dong Xie, Xinbo Chen, Yan Zhu, "Tackling Polytype Queries in Inconsistent Databases: Theory and Algorithm," Journal of Software vol. 7, no. 8, pp. 1861-1866, 2012.

General Information

ISSN: 1796-217X (Online)
Frequency:  Quarterly
Editor-in-Chief: Prof. Antanas Verikas
Executive Editor: Ms. Yoyo Y. Zhou
Abstracting/ Indexing: DBLP, EBSCO, CNKIGoogle Scholar, ProQuest, INSPEC(IET), ULRICH's Periodicals Directory, WorldCat, etc
E-mail: jsweditorialoffice@gmail.com
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