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 (1979)
have shown that when the given dependencies are functional, the database scheme has a
lossless join if and only if one of the relation schemes is a key for the universal scheme. In
this note we 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 …

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 we 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 …