Re: 3vl 2vl and NULL

From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Mon, 05 Dec 2005 08:10:32 GMT
Message-ID: <YBSkf.177$FP6.52@newsread2.news.pas.earthlink.net>

dawn wrote:

> David  Cressey wrote:

>>[...]
>>Now, since the term NULL has produced so much controversy, I'm going to use
>>an alternate notation in this post. I'm going to use the marker "(no
>>comment)" to indicate a missing value. Now let's go through some cases,
>>in Q and A format.
>>
>>Q: is 4 greater than 3?
>>A: TRUE
>>
>>Q: is 4 equal to 4?
>>A: TRUE
>>
>>Q: is 4 equal to 3?
>>A: FALSE
>>
>>Q: is 4 greater than (no comment)?
>>A: (no comment)

> 
> Here is where you are injecting a third value where I just think it is
> so much easier to work with a 2VL.  You do need to define some
> orderings, such as deciding that all sets of numbers are greater than
> empty sets, for example.  So, of this comparison, I don't want some
> silly third value to come in without some great benefit to my
> application (I can imagine an application where there would be an
> advantage to using fuzzy set logic, but that isn't the average data
> processing 101 app).
> 
> So, my answer is
> A: TRUE

Hi Dawn,

If the questions were as follows, what are your answers?

Q: is 4 less than (no comment)?
Q: is 4 equal to (no comment)?
Q: (is 4 less than (no comment)) AND (is 4 greater than (no comment))?
Q: (is 4 less than (no comment)) AND (is 4 greater than (no comment))
     AND (is 4 equal to (no comment))?
Q: (is 4 less than (no comment)) AND NOT (is 4 greater than (no
     comment))?

I won't list more questions until you have provided answers.

-- 
Jonathan Leffler                   #include <disclaimer.h>
Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com
Guardian of DBD::Informix v2005.02 -- http://dbi.perl.org/

Received on Mon Dec 05 2005 - 02:10:32 CST