Influences of Functional Dependencies on Bucket-Based Rewriting Algorithms
There are several algorithms for the problem of query rewriting using views, including the bucket-based algorithms and the inverse rule-based algorithms. The inverse rule-based algorithms have considered the problem in the presence of functional dependencies. However, there are few papers that consider the influences of functional dependencies from the point of view of the bucket-based algorithms. In this paper, we discuss this issue in the bucket-based framework. We mainly consider how to use conditions weaker than the ones in the previous algorithms when forming a set of buckets. The novelty of our approach is that we can enforce additional constraints on the non-exported attributes in a view through functional dependencies. As a result, more valid buckets can be formed. We can then generate additional rewritings which cannot be generated by the previous algorithms. We prove that our algorithm is sound and complete, i.e., the union of the obtained rewriting is a maximally-contained rewriting relative to functional dependencies under certain assumptions. In addition, we also discuss how to construct a recursive rewriting by making use of functional dependencies.
KeywordsFunctional Dependency Shared Variable Query Language Previous Algorithm Conjunctive Query
Unable to display preview. Download preview PDF.
- 1.Bai, Q., Hong, J., McTear, M.F.: Scalable Query Reformulation Using Views in the Presence of Functional Dependencies. In: Proceedings of the 4th International Conference on Advances in Web-Age Information Management, Chengdu, China, pp. 471–482. Springer, Heidelberg (2003)Google Scholar
- 2.Duschka, O.M., Genesereth, M.R.: Answering Recursive Queries Using Views. In: Proceedings of the 16th ACM Conference on Principles of Database Systems (PODS 1997), Tucson, Arizona, USA, pp. 109–116. ACM Press, New York (1997)Google Scholar
- 6.Lenzerini, M.: Data Integration: A Theoretical Perspective. In: Proceedings of the 21st ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, Madison, Wisconsin, USA, pp. 233–246. ACM Press, New York (2002)Google Scholar
- 9.Pottinger, R., Levy, A.Y.: A Scalable Algorithm for Answering Queries Using Views. In: Proceedings of the 26th International Conference on Very Large Data Bases, Cairo, Egypt, pp. 484–495. Morgan Kaufmann Publishers, San Francisco (2000)Google Scholar
- 10.Qian, X.: Query folding. In: Proceedings of the 12th IEEE International Conference on Data Engineering, New Orleans, Louisiana, USA, pp. 48–55. IEEE Computer Society Press, Los Alamitos (1996)Google Scholar
- 11.Ullman, J.D.: Information Integration Using Logical Views. In: Afrati, F.N., Kolaitis, P.G. (eds.) ICDT 1997. LNCS, vol. 1186, pp. 19–40. Springer, Heidelberg (1996)Google Scholar