Abstract
In a relational database model, checking the contraints of join dependency involves examining a set of n tuples and solving m 1 constraint equalities. We derive a scheme called the (n,m)-JD in which the number of constraint equalities is reduced to m 2, by forming cyclic combinations of the (disjoint) elements of the partition and increasing the number of intersection operations to obtain the projections in the constraint equalities. The reduced set of constraint equalities results in less elementary checking operations and hence an overall increase in efficiency in the normalization effort. The relationship among (n,m)-JDs of various degrees and orders is also studied and formalised.
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7. References
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© 1991 Springer-Verlag Berlin Heidelberg
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Tan, K.P., Tan, T.C. (1991). An improved join dependency for efficient constraint checking. In: Dehne, F., Fiala, F., Koczkodaj, W.W. (eds) Advances in Computing and Information — ICCI '91. ICCI 1991. Lecture Notes in Computer Science, vol 497. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-54029-6_167
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DOI: https://doi.org/10.1007/3-540-54029-6_167
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