Re: NULLs: theoretical problems?

From: Bob Badour <>
Date: Wed, 08 Aug 2007 17:20:12 -0300
Message-ID: <46ba2544$0$4028$>

Jan Hidders wrote:

> On 8 aug, 21:10, Bob Badour <> wrote:

>>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?
> What makes you think they have anything in common?

Each relates to interpretation and to an abstract entity taken as a given. Received on Wed Aug 08 2007 - 22:20:12 CEST

Original text of this message