Re: A Normalization Question

> > I claim the string 'brown' is a fact.
>
> The string "brown" is a value.

The string 'brown' is a value in the context of a tuple and attribute, not by itself. Here we are discussing the string 'brown' by itself.

> For something to be a fact, it has to exist as part
> of proposition, with an associated predicate.

The proposition is 'brown is composed of b,r,o,w,n'. RM needs this spelled out in appropriately arranged attribute values of tuples to recognize it. Some people need this spelled out in a sentence, but the proposition is already there in 'brown' by itself.

> "X is composed of the symbols A, B, C, D, and E in that order."
> which is redundant and denormalized, because X -> A, B, C, D, E.

The reason it is not redundant in XDb1/TM is because X does not store copies of A, B, C, D, E; X only refers to them in that order.

> If we are to accept your definition of fact, we would have to
> conclude that every value is a fact, which is to say, every
> value is true.

:)

> Let us consider the boolean domain, with its
> two values, true and false. (I hope you are able to distinguish
> "true"-the-string from true-the-boolean.) We have claimed
> that every value is true; we must therefor assert that the
> value false is true. False is not true, therefore our assumption
> that every value is true is false.

The problem is the use of the word true in true proposition. Better to think of a proposition as either existing or not existing in a db.

> In a proposition/fact/table/struct/object/whatever, we
> have to consider the ramifications of different choices
> as to how we represent attributes. We can have the
> attribute value stored directly within the thing, or
> else we can have a reference to somewhere else. There
> are two cases to consider: the reference refers to a
> variable, and the reference refers to a constant. If the
> two attributes are in fact the same attribute, then we
> can have references in two places that each refer to
> the same variable. If they are different, we cannot
> do this, because to change one would mean changing
> the other, and that would break the idea that they are
> different.

The above has been explained several times in this thread and older threads. One can change the string 'brown' directly, which has a global affect. If this in not desired, one should change a thing's name/value from the appropriate thing and the code automatically unrelated from the original string/value, creates a new one, and re-relates. This is easily demonstrated with XDb1. Received on Sun Jul 18 2004 - 07:43:40 CEST