Re: Functional Dependencies > Uniqueness Constraints

Marshall wrote:
It is also true
that a system that supported FDs explicitly could express
everything that one that had only uniqueness could; in other
words, one concept is strictly more powerful than the other,
and I propose there is a language design principle that
says that in that situation, you should not include the weaker
concept.

By that reasoning, FDs shouldn't be included if you have general
database constraints. And I want those.

One side comment: I note that the use case for a means of abstracting
constraints seems to come up repeatedly.

Cf. C. J. Date: Database In Depth (2005), p. 174--175.
--
Jon
.