Re: Date's First Great Blunder
Date: 24 Apr 2004 20:32:12 -0700
Message-ID: <4b45d3ad.0404241932.4ba639d4_at_posting.google.com>
> From my perspective, predicate logic, and by extension, relational database
> logic, is not concerned with the result of arbitrary operations on data.
> It is concerned with predicates, truth statements.
> We would have to arrive at a common understanding here before continuing.
This is the crux of our disagreement then. I believe, a statement with NULL is not a truth statement. IMO, "John's age is {}" is not a truth statement with respect to reality or using reality as a reference.
Lets proceed with a simpler statement "color is {}". If I ask a person, to list colors, he may say: red, green, blue, etc. But he will not say colors are: null, unknown, unavailable, unknowable, toBeDetermined, etc. These colors don't exist in reality. No one has/will see them. They don't belong in the color set/class/domain.
Just because a model (RDM) makes such statements which include NULLs (or subsequently masks them with special values), doesn't mean that they are representative of reality. Received on Sun Apr 25 2004 - 05:32:12 CEST