Advertisement

Abstract

Answering queries using views is the problem which examines how to derive the answers to a query when we only have the answers to a set of views. Constructing rewritings is a widely studied technique to derive those answers. In this paper we consider the problem of existence of rewritings in the case where the answers to the views uniquely determine the answers to the query. Specifically, we say that a view set \({\cal{V}}\) determines a query Q if for any two databases D 1,D 2 it holds: \({\cal{V}} (D_1) = {\cal{V}} (D_2)\) implies Q(D 1) = Q(D 2). We consider the case where query and views are defined by conjunctive queries and investigate the question: If a view set \({\cal{V}}\) determines a query Q, is there an equivalent rewriting of Q using \({\cal{V}}\)? We present here interesting cases where there are such rewritings in the language of conjunctive queries. Interestingly, we identify a class of conjunctive queries, CQ path , for which a view set can produce equivalent rewritings for “almost all” queries which are determined by this view set. We introduce a problem which relates determinacy to query equivalence. We show that there are cases where restricted results can carry over to broader classes of queries.

Keywords

Query Language Conjunctive Query Path Query Answering Query View Versus 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Abiteboul, S., Duschka, O.M.: Complexity of answering queries using materialized views. In: PODS (1998)Google Scholar
  2. 2.
    Afrati, F., Li, C., Ullman, J.D.: Generating efficient plans using views. In: SIGMOD (2001)Google Scholar
  3. 3.
    Afrati, F., Li, C., Ullman, J.D.: Using views to generate efficient evaluation plans for queries. JCSS (to appear)Google Scholar
  4. 4.
    Afrati, F.N., Li, C., Mitra, P.: Rewriting queries using views in the presence of arithmetic comparisons. Theor. Comput. Sci. 368(1-2) (2006)Google Scholar
  5. 5.
    Agrawal, S., Chaudhuri, S., Narasayya, V.R.: Automated selection of materialized views and indexes in sql databases. In: Proc. of VLDB (2000)Google Scholar
  6. 6.
    Bayardo Jr., R.J., et al.: Infosleuth: Semantic integration of information in open and dynamic environments (experience paper). In: SIGMOD (1997)Google Scholar
  7. 7.
    Calvanese, D., De Giacomo, G., Lenzerini, M., Vardi, M.Y.: Lossless regular views. In: PODS, ACM, New York (2002)Google Scholar
  8. 8.
    Calvanese, D., De Giacomo, G., Lenzerini, M., Vardi, M.Y.: View-based query query processing: On the relationship between rewriting, answering and losslessness. In: International Conference on Database Theory (ICDT) (2005)Google Scholar
  9. 9.
    Chandra, A.K., Merlin, P.M.: Optimal implementation of conjunctive queries in relational data bases. In: STOC (1977)Google Scholar
  10. 10.
    Chaudhuri, S., Krishnamurthy, R., Potamianos, S., Shim, K.: Optimizing queries with materialized views. In: ICDE (1995)Google Scholar
  11. 11.
    Chawathe, S.S., et al.: The TSIMMIS project: Integration of heterogeneous information sources. In: IPSJ (1994)Google Scholar
  12. 12.
    Chekuri, C., Rajaraman, A.: Conjunctive query containment revisited. In: Afrati, F.N., Kolaitis, P.G. (eds.) ICDT 1997. LNCS, vol. 1186, Springer, Heidelberg (1996)Google Scholar
  13. 13.
    Duschka, O.M., Genesereth, M.R.: Answering recursive queries using views. In: PODS (1997)Google Scholar
  14. 14.
    Florescu, D., Levy, A., Suciu, D., Yagoub, K.: Optimization of run-time management of data intensive web-sites. In: Proc. of VLDB (1999)Google Scholar
  15. 15.
    Grumbach, S., Tininini, L.: On the content of materialized aggregate views. In: PODS (2000)Google Scholar
  16. 16.
    Haas, L.M., Kossmann, D., Wimmers, E.L., Yang, J.: Optimizing queries across diverse data sources. In: Proc. of VLDB (1997)Google Scholar
  17. 17.
    Halevy, A.Y.: Answering queries using views: A survey. VLDB Journal 10(4)Google Scholar
  18. 18.
    Ives, Z., Florescu, D., Friedman, M., Levy, A., Weld, D.: An adaptive query execution engine for data integration. In: SIGMOD (1999)Google Scholar
  19. 19.
    Levy, A., Mendelzon, A., Sagiv, Y., Srivastava, D.: Answering queries using views. In: PODS (1995)Google Scholar
  20. 20.
    Levy, A., Rajaraman, A., Ordille, J.J.: Querying heterogeneous information sources using source descriptions. In: Proc. of VLDB (1996)Google Scholar
  21. 21.
    Li, C., Bawa, M., Ullman, J.: Minimizing view sets without losing query-answering power. In: Van den Bussche, J., Vianu, V. (eds.) ICDT 2001. LNCS, vol. 1973, Springer, Heidelberg (2000)Google Scholar
  22. 22.
    Nash, A., Segoufin, L., Vianu, V.: Determinacy and rewriting of conjunctive queries using views: A progress report. In: Schwentick, T., Suciu, D. (eds.) ICDT 2007. LNCS, vol. 4353, Springer, Heidelberg (2006)Google Scholar
  23. 23.
    Rajaraman, A., Sagiv, Y., Ullman, J.D.: Answering queries using templates with binding patterns. In: PODS (1995)Google Scholar
  24. 24.
    Segoufin, L., Vianu, V.: Views and queries: Determinacy and rewriting. In: PODS, ACM Press, New York (2005)Google Scholar
  25. 25.
    Theodoratos, D., Sellis, T.: Data warehouse configuration. In: Proc. of VLDB (1997)Google Scholar
  26. 26.
    Ullman, J.D.: Information integration using logical views. In: Afrati, F.N., Kolaitis, P.G. (eds.) ICDT 1997. LNCS, vol. 1186, Springer, Heidelberg (1996)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • Foto Afrati
    • 1
  1. 1.National Technical University of AthensGreece

Personalised recommendations