Re: NULLs: theoretical problems?

On 8 aug, 21:10, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> Jan Hidders wrote:
> > On 8 aug, 17:09, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
> >>Jan Hidders wrote:
>
> >>>On 8 aug, 14:26, Bob Badour <bbad..._at_pei.sympatico.ca> 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.
>
> >>How
> >>exactly does that differ from scriptural interpretation and theories
> >>thereof?
>
> > 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?

• Jan Hidders