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Recognition And Top-Down Generation Of Beta-Acyclic Database Schemes

Lakshmanan, VS and Chandrasekaran, N and Madhavan, CEV (1984) Recognition And Top-Down Generation Of Beta-Acyclic Database Schemes. In: Lecture Notes In Computer Science, 181 . pp. 344-366.

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Database schemes can be viewed as hypergraphs with individual relation schemes corresponding to the edges of a hypergraph. Under this setting, a new class of "acyclic" database schemes was recently introduced and was shown to have a claim to a number of desirable properties. However, unlike the case of ordinary undirected graphs, there are several unequivalent notions of acyclicity of hypergraphs. Of special interest among these are agr-, beta-, and gamma-, degrees of acyclicity, each characterizing an equivalence class of desirable properties for database schemes, represented as hypergraphs. In this paper, two complementary approaches to designing beta-acyclic database schemes have been presented. For the first part, a new notion called "independent cycle" is introduced. Based on this, a criterion for beta-acyclicity is developed and is shown equivalent to the existing definitions of beta-acyclicity. From this and the concept of the dual of a hypergraph, an efficient algorithm for testing beta-acyclicity is developed. As for the second part, a procedure is evolved for top-down generation of beta-acyclic schemes and its correctness is established. Finally, extensions and applications of ideas are described.

Item Type: Journal Article
Publication: Lecture Notes In Computer Science
Publisher: Springer
Additional Information: Copyright of this article belongs to Springer.
Department/Centre: Division of Electrical Sciences > Computer Science & Automation
Date Deposited: 10 Feb 2010 06:23
Last Modified: 10 Feb 2010 06:23
URI: http://eprints.iisc.ac.in/id/eprint/22323

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