Advertisement

On the Containment of Conjunctive Queries

  • Georg Lausen
  • Fang Wei
Chapter
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2598)

Abstract

Testing containment of conjunctive queries is the question whether for any such queries Q1,Q2, for any database instance D, the set of answers of one query is contained in the set of answers of the other. In this paper, we first introduce into the general approach for testing for the case, when both queries do not contain negation. Based on these techniques we discuss the question for the case of queries with negation. We propose a new method and compare with the currently known approach. Instead of always testing the exponential number of possible canonical databases, our algorithm will terminate once a certain canonical database is constructed. However, in the worst case, still an exponential number of canonical databases has to be checked.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    S. Abiteboul and O. M. Duschka. Complexity of answering queries using materialized views. In ACM Symp. on Principles of Database Systems (PODS), 1998.Google Scholar
  2. 2.
    A. K. Chandra and P. M. Merlin. Optimal implementations of conjunctive queries in relational data bases. In ACM Symp. on Theory of Computing (STOC), pages 77–90. 1977.Google Scholar
  3. 3.
    O. M. Duschka and A. Y. Levy. Recursive plans for information gathering. In International Joint Conference on Artificial Intelligence (IJCAI), pages 778–784, 1997.Google Scholar
  4. 4.
    S. Flesca and S. Greco. Rewriting queries using views. In TKDE, 13(6), 2001.Google Scholar
  5. 5.
    D. Florescu, A. Levy, and D. Suciu. Query containment for conjunctive queries with regular expressions. In ACM Symp. on Principles of Database Systems (PODS). 1998.Google Scholar
  6. 6.
    A. Gupta, Y. Sagiv, J. D. Ullman, and J. Widom. Constraint checking with partial information. In ACM Symp. on Principles of Database Systems (PODS). 1994.Google Scholar
  7. 7.
    A. Halevy. Answering queries using views: A survey. In VLDB Journal, 10:4, pp. 270–294, 2001.zbMATHCrossRefGoogle Scholar
  8. 8.
    A. Klug. On conjunctive queries containing inequalities. In Journal of the ACM35:1, pp. 146–160, 1988.zbMATHCrossRefMathSciNetGoogle Scholar
  9. 9.
    A. Y. Levy, A. O. Mendelzon, Y. Sagiv, and D. Srivastava. Answering queries using views. In ACM Symp. on Principles of Database Systems (PODS). 1995.Google Scholar
  10. 10.
    A. Levy and Y. Sagiv. Queries independent of updates. In International Conference on Very Large Data Bases (VLDB), 1993.Google Scholar
  11. 11.
    A. Levy and D. Suciu. Deciding containment for queries with complex objects. In ACM Symp. on Principles of Database Systems (PODS). ACM Press, 1997.Google Scholar
  12. 12.
    Y. Sagiv and M. Yannakakis. Equivalence among relational expressions with the union and difference operations. Journal of the ACM, (4), 27(4):633–655, 1980.zbMATHCrossRefMathSciNetGoogle Scholar
  13. 13.
    J. Ullman. Principles of Database and KnowledgeBase Systems, Volume II. 1989.Google Scholar
  14. 14.
    J. Ullman. Principles of Database Systems — Lecture Notes. http://www.dbstanford.edu/ullman/cs345-notes.html..
  15. 15.
    J. D. Ullman. Information integration using logical views. In International Conference on Database Theory (ICDT), 1997.Google Scholar
  16. 16.
    X. Zhang and Z. Meral Özsoyoglu. On efficient reasoning with implication constraints. In DOOD, pages 236–252, 1993.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  • Georg Lausen
    • 1
  • Fang Wei
    • 1
  1. 1.Institute for Computer ScienceUniversity of FreiburgGermany

Personalised recommendations