Re: Functional Dependency to constrain a relation to exactly one element?

Bob Badour ha escrito:

> I think he was referring to the existential constraint.

Indeed, sorry.

> Assuming the
> dbms treats DEE as true, all one needs to provide for the constraint is
> a projection onto zero attributes:
>
> var R relation { ... } key {} constraint {},
> insert R ...;

Elegant solution. Another way could be to use: not IsEmpty().

Regards
  Alfredo Received on Mon Oct 02 2006 - 11:41:02 CDT