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On the First-Order Reducibility of Unions of Conjunctive Queries over Inconsistent Databases

  • Domenico Lembo
  • Riccardo Rosati
  • Marco Ruzzi
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4254)

Abstract

Recent approaches in the research on inconsistent databases have started analyzing the first-order reducibility of consistent query answering, i.e., the possibility of identifying classes of queries whose consistent answers can be obtained by a first-order (FOL) rewriting of the query, which in turn can be easily formulated in SQL and directly evaluated through any relational DBMS. So far, the investigations in this direction have only concerned subsets of conjunctive queries over databases with key dependencies. In this paper we extend the study of first-order reducibility of consistent query answering under key dependencies to more expressive queries, in particular to unions of conjunctive queries. More specifically: (i) we analyze the applicability of known FOL-rewriting techniques for conjunctive queries in the case of unions of conjunctive queries. It turns out that such techniques are applicable only to a very restricted class of unions of conjunctive queries; (ii) to overcome the above limitations, we define a new rewriting method which is specifically tailored for unions of conjunctive queries. The method can be applied only to unions of conjunctive queries that satisfy an acyclicity condition on unions of conjunctive queries.

Keywords

Database Schema Relation Symbol Conjunctive Query Database Instance Head Variable 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Abiteboul, S., Hull, R., Vianu, V.: Foundations of Databases. Addison Wesley Publ. Co., Reading (1995)MATHGoogle Scholar
  2. 2.
    Arenas, M., Bertossi, L.E., Chomicki, J.: Consistent query answers in inconsistent databases. In: Proceedings of the Eighteenth ACM Sigact Sigmod Sigart Symposium on Principles of Database Systems (PODS 1999), pp. 68–79 (1999)Google Scholar
  3. 3.
    Bravo, L., Bertossi, L.: Logic programming for consistently querying data integration systems. In: Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence (IJCAI 2003), pp. 10–15 (2003)Google Scholar
  4. 4.
    Calì, A., Lembo, D., Rosati, R.: On the decidability and complexity of query answering over inconsistent and incomplete databases. In: Proceedings of the Twentysecond ACM Sigact Sigmod Sigart Symposium on Principles of Database Systems (PODS 2003), pp. 260–271 (2003)Google Scholar
  5. 5.
    Calì, A., Lembo, D., Rosati, R.: Query rewriting and answering under constraints in data integration systems. In: Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence (IJCAI 2003), pp. 16–21 (2003)Google Scholar
  6. 6.
    Chomicki, J., Marcinkowski, J.: On the computational complexity of minimal-change integrity maintenance in relational databases. In: Bertossi, L., Hunter, A., Schaub, T. (eds.) Inconsistency Tolerance. LNCS, vol. 3300, pp. 119–150. Springer, Heidelberg (2005)CrossRefGoogle Scholar
  7. 7.
    Chomicki, J., Marcinkowski, J., Staworko, S.: Computing consistent query answers using conflict hypergraphs. In: Proceedings of the Thirteenth International Conference on Information and Knowledge Management (CIKM 2004), pp. 417–426 (2004)Google Scholar
  8. 8.
    Eiter, T., Fink, M., Greco, G., Lembo, D.: Efficient evaluation of logic programs for querying data integration systems. In: Palamidessi, C. (ed.) ICLP 2003. LNCS, vol. 2916, pp. 163–177. Springer, Heidelberg (2003)CrossRefGoogle Scholar
  9. 9.
    Fuxman, A., Fazli, E., Miller, R.J.: ConQuer: Efficient management of inconsistent databases. In: Proceedings of the ACM SIGMOD International Conference on Management of Data, pp. 155–166 (2005)Google Scholar
  10. 10.
    Fuxman, A.D., Miller, R.J.: First-order query rewriting for inconsistent databases. In: Eiter, T., Libkin, L. (eds.) ICDT 2005. LNCS, vol. 3363, pp. 337–351. Springer, Heidelberg (2004)CrossRefGoogle Scholar
  11. 11.
    Greco, G., Greco, S., Zumpano, E.: A logical framework for querying and repairing inconsistent databases. IEEE Transactions on Knowledge and Data Engineering 15(6), 1389–1408 (2003)CrossRefGoogle Scholar
  12. 12.
    Grieco, L., Lembo, D., Ruzzi, M., Rosati, R.: Consistent query answering under key and exclusion dependencies: Algorithms and experiments. In: Proceedings of the Fourteenth International Conference on Information and Knowledge Management (CIKM 2005), pp. 792–799 (2005)Google Scholar
  13. 13.
    Leone, N., Pfeifer, G., Faber, W., Eiter, T., Gottlob, G., Perri, S., Scarcello, F.: The DLV system for knowledge representation and reasoning. ACM Transactions on Computational Logic (to appear, 2006)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Domenico Lembo
    • 1
  • Riccardo Rosati
    • 1
  • Marco Ruzzi
    • 1
  1. 1.Dipartimento di Informatica e SistemisticaUniversità di Roma “La Sapienza”RomaItaly

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