Re: NULLs: theoretical problems?

From: Bob Badour <>
Date: Wed, 08 Aug 2007 16:10:34 -0300
Message-ID: <46ba14f1$0$4063$>

Jan Hidders wrote:

> On 8 aug, 17:09, Bob Badour <> wrote:

>>Jan Hidders wrote:
>>>On 8 aug, 14:26, Bob Badour <> wrote:
>>>>sinister wrote:
>>>>>Many discussions point out one deficiency of NULLs: that they collapse
>>>>>multiple, distinct concepts into one ("no value possible," "value missing,"
>>>>>"value not available at this time", etc).
>>>>>What are the other theoretical problems? My impression from skimming some
>>>>>threads in this ng is that some anomalies might occur, maybe having to do
>>>>>with NULLs and joins, or NULLs and keys composed of more than one field, but
>>>>>I'm not sure.
>>>>The ultimate theoretical problem is a complete lack of any theory
>>>>underpinning NULL.
>>>Just to avoid any misunderstandings: there has of course been lots of
>>>theory on certain interpretations of null values, such as the work by
>>>Raymond Reiter and by Joachim Biskup, but not on the specific meaning
>>>(if you can call it that) that they were given in SQL. Whether that is
>>>necessarily a big problem is IMO not so easy to say.
>>In other words, some folks accept that NULL exists without any
>>theoretical underpinning and then create theories of interpretation.
> Indeed. Because, as we all know, proposing and investigating
> alternatives is the same as accepting something's existence.

>>exactly does that differ from scriptural interpretation and theories
> Exactly! Rejecting straight away null values in any form or shape
> without any sort of investigation of their properties would have been
> much more scientific. :-)

That doesn't answer the question. How does it differ from scriptural interpretation and theories thereof? Received on Wed Aug 08 2007 - 21:10:34 CEST

Original text of this message