Re: Unique constraint and NULL values

From: DA Morgan <damorgan_at_x.washington.edu>
Date: Fri, 29 Oct 2004 18:08:43 -0700
Message-ID: <1099098462.431138@yasure>

Hans Wijte wrote:

> 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

Not the same book.

I said "Expert one-on-one Oracle."

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)

Received on Fri Oct 29 2004 - 20:08:43 CDT