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Re: Two-valued logic

From: Dawn M. Wolthuis <dwolt_at_tincat-group.com>
Date: Sun, 28 Dec 2003 18:34:24 -0600
Message-ID: <bsnsqv$jck$1@news.netins.net>


"Marshall Spight" <mspight_at_dnai.com> wrote in message news:_sKHb.502995$275.1414945_at_attbi_s53...
> "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message
news:bsnp6q$fdn$1_at_news.netins.net...
> > I work with a model that uses a two-valued logic. A NULL value under
this
> > scenario can be handled logically as a null set value. With this model,
a
> > NULL then = a NULL because a null set equals a null set..
>
> I'm not sure I understand. Are you saying that your model includes
> the empty set? That seems sound if unremarkable.
>

Yes, it is both sound and unremarkable (quite like the rest of the model -- it just "thinks" the way a regular person -- me, for example -- suspects it will). The two-valued logic definitely provides challenges when one chooses to issue SQL commands via ODBC or JDBC, however, rather than using a language that works with two-valued data and perceives nulls as a value rather than the lack of a value.

<snip>
> The one person I respect who defends nulls is Lee Fesperman. He
> has a web site for his RDBMS product; there are whitepapers
> there that cover his reasoning.
>
> His website:
> http://firstsql.com/
>
> "In Defense of Nulls"
> http://firstsql.com/idefend.htm
>
> For myself, I dislike 3VL, since I think it adds tremendous complexity
> but little expressiveness. The expressiveness it does add would be
> better dealt with in the type system, and not in the logic system.
>
>
> Marshall

A very helpful and much appreciated response, Marshall. Thanks! --dawn Received on Sun Dec 28 2003 - 18:34:24 CST

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