--CELKO-- <71062.1056_at_compuserve.com> wrote in message
news:c0d87ec0.0112041036.75c1d6e0_at_posting.google.com...
>
> There are also strong JPNF and overstrong JPNF, which make use of JOIN
> dependencies (JD for short). Unfortunately, there is no systematic
> way to find a JPNF or 4NF schema, because the problem is known to be
> NP complete.
Which problem exactly? I know that the problem of deciding if a relation is
in BCNF is already NP complete if all you have is the FDs. However, this
changes if you know already the candidate keys. I believe the same holds for
deciding if a relation is in PJ/NF.
Received on Wed Dec 05 2001 - 06:06:50 CST
