Re: Unique constraint and NULL values

DA Morgan <damorgan_at_x.washington.edu> wrote in message news:<1098427498.727456_at_yasure>...
> David Portas wrote:
> > There is no documented method of making unique constraints ANSI-compliant in
> > MS SQL Server 7.0 or 2000. There are some workarounds but no supported
> > configuration parameter for changing the unique constraint behaviour.
> >
> > I would be very surprised if there is such an undocumented feature but if
> > you know differently can you post an example or a reference?
>
> I'm not a SQL Server expert but Tom Kyte makes reference to it in Expert
> One-on-one Oracle. I've loaned my copy of the book to another instructor
> until he gets his own so I can't quote the page and paragraph.
>
> If Kyte says it is there ... I'm inclined toward believing that it is,
> indeed, there.

in my copy of Tom Kytes "Expert 101 Oracle" he makes no such reference; actually he implies (page 38) that setting a specific variable to null
("L-SOME_VARIABLE" he calls it) in a piece of coding a certain query didn't
return rows while a SQL Server schooled developer expected it to. He doesn't suggest that this is an undocumented feature or that such a variable really exists, but that this is solely due to a difference between Oracle and SQL Server (or Sybase) in the handling of null values

Hans Wijte Received on Fri Oct 29 2004 - 04:55:07 CDT