Re: So what's null then if it's not nothing?
From: Hugo Kornelis <hugo_at_pe_NO_rFact.in_SPAM_fo>
Date: Fri, 18 Nov 2005 01:41:06 +0100
Message-ID: <pl8qn1tsnu9sbogotk4kipspqdqfb15v59_at_4ax.com>
Date: Fri, 18 Nov 2005 01:41:06 +0100
Message-ID: <pl8qn1tsnu9sbogotk4kipspqdqfb15v59_at_4ax.com>
On Thu, 17 Nov 2005 10:27:55 -0600, N. Shamsundar wrote:
(sniip)
>Try this: every logical expression has three possible values, not two as
>in languages such as C, Pascal, Fortran, etc. They are, as you seem to
>have recognized, "TRUE", "FALSE" and "UNKNOWN" (named "NULL" in SQL).
Hi N.,
This is incorrect. "UNKNOWN" is not named "NULL" in SQL. See my long post to Mike.
> If
>you keep this in mind and refrain from using other notions such as the
>NULL in C (a pointer value that you may not dereference, etc.)
Since SQL's Null is a marker or the absence of a value and C's NULL is a pointer to nothing, they are in fact more similar than you seem to suggest here.
Best, Hugo
-- (Remove _NO_ and _SPAM_ to get my e-mail address)Received on Fri Nov 18 2005 - 01:41:06 CET