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Erschienen in:
2012 | OriginalPaper | Buchkapitel
BCNF via Attribute Splitting
verfasst von : Johann A. Makowsky, Elena V. Ravve
Erschienen in: Conceptual Modelling and Its Theoretical Foundations
Verlag: Springer Berlin Heidelberg
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Boyce-Codd-Heath introduced criteria for good database design, which can be formulated in terms of FD’s only. Classical design decomposes relations iteratively using projections. BCNF can not be always achieved using projections alone. 3NF was introduced as a compromise. In this paper we summarize all the known characterizations of BCNF and formulate a new one. In [MR96], attribute splitting was suggested as a heuristics to achieve BCNF in case projections do not do the job. Here we show how attribute splitting can be used to restructure a database scheme iteratively such that the result will be in BCNF, is information preserving and preserves the functional dependencies.