Abstract
Let ϕ: ℜ→L be a mapping between databases over (different) schemes R and S. This paper considers the following question. What can we say about dependencies in ϕ(r) if we know dependencies in r ∈ ℜ. It is shown that under some conditions the existence of a sound and complete inference system for ℜ implies the existence of a sound and complete inference system for the triple (ℜ, ϕ, L). In the case of functional dependencies some necessary and sufficient conditions for the existence of a sound and complete inference system for the triple (ℜ, ϕ, L) is obtained. However, these conditions are rather strong. But these conditions could be eliminated if we extend the language for dependencies' description. The so called (untyped) mixed functional dependencies that generalize the functional ones are introduced. For these dependencies a sound and complete inference system D is constructed. Moreover, from the system D and the mapping ϕ a sound and complete inference system for the triple (ℜ, ϕ, L) is obtained.
Preview
Unable to display preview. Download preview PDF.
References
Aho A.V., Beeri C., Ullman J.D. The theory of joins in relational databases. ACM Trans. Database Syst., 4(1979), N3, 297–314.
Armstrong W.W. Dependency structures of data base relations-hips. 1974 IFIP Congr., 580–583.
Chan E.P.F., Mendelzon A.O. Independent and separable database schemes. In Procceedings of the 2nd ACM Symposium on Principles of Database Systems. ACM, New York, 1983, 288–296.
Graham M.C., Mendelzon A.O., Vardi M.Y. Notions on dependency satisfaction. J. ACM, 1986, v. 33, N1, 105–129.
Graham M.C., Yannakakis M. Independent database schemas. J. Comput. Syst. Sci., 1984, v. 28, N1, 121–141.
Grant J., Jacobs B.E. On the family of generalized dependency constraints. J. ACM, 1982, v.29, N4, 986–997.
Honeyman P. Testing satisfaction of functional dependencies. J. ACM, 1982, v. 29, N3, 668–677.
Imelinski T., Spyratos N. On lossless transformation of database schemes not necessarily satisfying universal instance assumption. Proc. 3d ACM Symp. Princip. Database Syst., 1984, 258–265.
Maier D. The Theory of Relational Databases. Comput. Sci. Press, 1983.
Maier D., Mendelzon A.O., Sadri F., Ullman J.D. Adequacy of decompositions of relational databases. J. Comp. Syst. Sci., 21(1980), N3, 368–379.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1989 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Komissartschik, E.A. (1989). Restructuring and dependencies in databases. In: Demetrovics, J., Thalheim, B. (eds) MFDBS 89. MFDBS 1989. Lecture Notes in Computer Science, vol 364. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-51251-9_18
Download citation
DOI: https://doi.org/10.1007/3-540-51251-9_18
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-51251-6
Online ISBN: 978-3-540-46182-1
eBook Packages: Springer Book Archive