On Thu, 2003-06-05 at 15:39, Jon Earle wrote:
> On Wed, 4 Jun 2003 terry@ashtonwoodshomes.com wrote:
>
> > Oracle *incorrectly* interprets blank (empty) strings as NULL. They are NOT
> > the same. A string of zero characters is a string nonetheless. A NULL is
> > "the absence of value", which equals nothing (theoretically not even another
> > NULL).
>
> If you're testing a value, you're testing to see if there's something in
> there or not - what difference does it make if the variable contains 0, ""
> or NULL?
>
> Why not adhere to the practices inherent (and thus anticipated by
> developers) in other languages (C comes to mind) where 0, NULL and "" are
> equivalent?
>
> Cheers!
No! For me it is very important that NULL does not equal 0 or "",
because we have a database where a value of 0 means 0 and a NULL means
that the data normally stored there is not applicable for that record.
We calculate averages on the fields, and we don't want 'not applicable'
values to affect the average.
In any case, this is actually in line with languages like C, because
NULL means that no memory has been assigned to a variable, it does not
mean that the value stored in that variable is 0, or even "".
NULL, 0 and "" are definitely not the same thing in C. If you see them
as the same, you are just looking for segmentation faults. :-)
In any case, NULL should not equal 0, as 0 is a value (between -1 and
1), while NULL is nothing, you cannot compare it to another value.
Is NULL smaller or larger than 1?
--
Andre Truter
Software Engineer
Registered Linux user #185282
ICQ #40935899 AIM: trusoftzaf
http://www.trusoft.za.net
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< The box said: Requires Windows 95 or better... >
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