Re: NULL

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Wed, 08 Jun 2005 21:28:18 +0200
Message-ID: <42a746cd$0$46101$e4fe514c@news.xs4all.nl>

Jan Hidders wrote:

> mAsterdam wrote:

>>
>> Earlier I wrote (in fact _we_ wrote, I summarized):
>>
>>> [NULL]
>>> The insanity bit. No! The humility marker.
>>> mu: The absence of an answer to a question which requires an answer.
>>>
>>> /adj./
>>> 1. Attributes to something the absence of values.
>>> Ex: "The *null* set is the empty set, often represented by {}."
>>>
>>> /n. colloq./
>>> 1. A noted appearance of the absence of values.
>>> Ex: "This table contains *nulls*."
>>>
>>> Common usage:
>>>
>>> - Confusion arises when people use terms like "null value",
>>> a paradox to some, a contradictio in terminis to others.
>>>
>>> - Confusion arises due to the fact that nullness (the absence of value)
>>> is often represented on computers by the number 0.
>>> (Obviously, 0 is not null.)
>>>
>>> - In some contexts, 'null' and 'nil' mean the same thing; in others,
>>> they do not.
>>>
>>> In databases traditionally NULL is used and and opposed.
>>> If you want to go into this, please first search for
>>> mu NIL void NULL undef, 2VL 3VL.
>>>
>>> "It isn't the things we don't know that give us trouble.
>>> It's the things we know that ain't so." - Will Rogers
>>
>>
>> I now think this is to much from the "NULL is the absence of value"
>> point of view. Any suggestions for improvement?

> 
> 
> I'm still a bit puzzled by this list. What is it exactly that you want 
> to achieve with it? I thought the point was to avoid confusion over 
> important terms in database theory. In this form it IMO only adds to the 
> confusion. But maybe I'm wrong about its goal, I wasn't around when you 
> guys started this.

The point was/is to avoid specific confusions - the ones which arise when somebody uses a term from his/her own experience - wrongly assuming most readers have the same connotations.

At the time there were lengthy threads eventually resolving to dissapointingly simple interpretation differences. IMHO the glossary did a nice job for most of the other terms in the list. (MV, data, relation/relationship).

The NULL entry in its current incarnation appears to not help at all, though.

What makes it worse: NULL is a special case. People tend to just use the term and assign to it whatever meaning they want - even different meanings in different posts.

So, I think a better text is needed.
Help is appreciated. Received on Wed Jun 08 2005 - 14:28:18 CDT