Abstract
Partial functional dependencies, functional dependencies accompanied by a factor, are examined in a relational database based on or-sets. The partial functional dependencies are dealt with under tuples having their belongingness degree to a relation. Whether a functional dependency accompanied by a factor holds in a relation is determined by comparing the factor with to what degree the relation satisfies the functional dependency. Inference rules, similar to Armstrong’s axioms in the conventional relational databases, are obtained. Thus, we can discover another functional dependencies related with a partial functional dependency by using the inference rules.
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Gediga, G. and Düntsch, I. [2001] Rough Approximation Quality Revisited, Artificial Intelligence, 132, 219–234.
Lin, T. Y. and Cercone, N., eds. [1997] Rough Sets and Data Mining: Analysis for Imprecise Data, Kluwer Academic Publishers 1997.
Lipski, W. [1979]On Semantics Issues Connected with Incomplete Information Databases. ACM Transactions on Database Systems, 4:3, 262–296.
Nakata, M. [2000] On Inference Rules of Dependencies in Fuzzy Relational Data Models: Functional Dependencies, in Knowledge Management in Fuzzy Databases, Eds., O. Pons, M. A. Vila, and J. Kacprzyk, Physica Verlag, pp. 36–66.
Novotný, M. and Pawlak, Z. [1988] Partial Dependencies of Attributes, Bulletin of the Polish Academy of Sciences, 36(7-8), 453–458.
Parsons, S. [1996] Current Approaches to Handling Imperfect Information in Data and Knowledge Bases, IEEE Transactions on Knowledge and Data Engineering, 8:3, 353–372.
Pawlak, Z. [1991] Rough Sets: Theoretical Aspects of Reasoning about Data, Kluwer Academic Publishers 1991.
Vassiliou, Y. [1980]Functional Dependencies and Incomplete Information, in Proceedings of the 6th VLDB Conference, pp. 260–269.
Ziarko, W. [1991]The Discovery, Analysis, and Representation of Data Dependencies in Databases, in: Knowledge Discovery in Databases, Eds., G. Piatetsky and W. J. Frawley, AAAI Press/ The MIT Press 1991, pp. 195–209.
Ziarko, W. P., ed. [1994] Rough Sets, Fuzzy Sets and Knowledge Discovery, Springer 1994.
Zimányi, E. [1997]Query Evaluation in Probabilistic Relational Databases, Theoretical Computer Science, 171, 179–220.
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© 2002 Springer-Verlag Berlin Heidelberg
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Nakata, M., Murai, T. (2002). Functional Dependencies in Relational Expressions Based on Or-Sets. In: Alpigini, J.J., Peters, J.F., Skowron, A., Zhong, N. (eds) Rough Sets and Current Trends in Computing. RSCTC 2002. Lecture Notes in Computer Science(), vol 2475. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45813-1_20
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DOI: https://doi.org/10.1007/3-540-45813-1_20
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