Accession Number : ADA141488

Title :   A Note on Lossless database Decompositions.

Descriptive Note : Technical rept.,

Corporate Author : STANFORD UNIV CA DEPT OF COMPUTER SCIENCE

Personal Author(s) : Vardi, M Y

PDF Url : ADA141488

Report Date : 21 Dec 1983

Pagination or Media Count : 11

Abstract : It is known that under a wide variety of assumptions a database decomposition is lossless if and only if the database scheme has a lossless join. Biskup, Dayal, and Bernstein have shown that when the given dependencies are functional then the database scheme has a lossless join if and only if one of the relation scheme is a key for the universal scheme. In this note the investigators supply an alternative proof of that characterization. The proof uses tools from the theory of embedded join dependencies and the theory of tuple and equality generating dependencies, but is, nevertheless, much simpler than the previously published proof. (Author)

Descriptors :   *DATA BASES, *DECOMPOSITION, EMBEDDING, THEOREMS

Subject Categories : Information Science

Distribution Statement : APPROVED FOR PUBLIC RELEASE