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$FP6.52_at_newsread2.news.pas.earthlink.net>
>>[...]
>>Now, since the term NULL has produced so much controversy, I'm going to use
>>an alternate notation in this post. I'm going to use the marker "(no
>>comment)" to indicate a missing value. Now let's go through some cases,
>>in Q and A format.
>>
>>Q: is 4 greater than 3?
>>A: TRUE
>>
>>Q: is 4 equal to 4?
>>A: TRUE
>>
>>Q: is 4 equal to 3?
>>A: FALSE
>>
>>Q: is 4 greater than (no comment)?
>>A: (no comment)
Date: Mon, 05 Dec 2005 08:10:32 GMT
Message-ID: <YBSkf.177$FP6.52_at_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 - 09:10:32 CET