Designing alpha-acyclic BCNF-database schemes

  • Detlev Ruland
  • Dietmar Seipel
Contributed Papers
Part of the Lecture Notes in Computer Science book series (LNCS, volume 305)


The problem of designing database schemes satisfying the three design properties lossless join, Boyce-Codd normal form and α-acyclicity is considered. First, it is shown by a sample relation scheme, that these three properties are not always obtainable. This result is independent of any design method. Secondly, the problem of using the BCNF-decomposition algorithm for designing database schemes, which are additionally α-acyclic, is investigated. A characterization of those decomposotion processes yielding α-acyclic, lossless database schemes is given.

The main result of the paper is, that for each relation scheme an α-acyclic, lossless BCNF-database scheme can be constructed. This goal is reached by using the concept of lattice compatible augmentation, cf. /KaMa 80/, i.e. the original relation scheme is expanded by additional surrogate attributes (and related functional dependencies). Moreover, this result yields a modified two phase BCNF-decomposition algorithm.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • Detlev Ruland
    • 1
  • Dietmar Seipel
    • 2
  1. 1.IBM Almaden Research CenterSan Jose
  2. 2.Lehrstuhl für Informatik IUniversity WürzburgWürzburgW.-Germany

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