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Re: Operationalize orthogonality

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Sun, 04 Jun 2006 13:00:11 +0200
Message-ID: <4482bcc7$0$31648$e4fe514c@news.xs4all.nl>


Tony D wrote:
> The only type absolutely required is the boolean type. You could (and I
> stress, *could*) attempt to model everything from there on up in terms
> of relations and booleans, but that would require a frightening degree
> of circumlocution.

Yes. Let's not go that way.

> Any real system would have to provide some basic types and operators on
> those types, along with a method of generating your own types and
> associated operators. (Internally, these types and operators might be
> defined in terms of relations and booleans, but those details would be
> carefully hidden under the covers.) The only requirement on those types
> for use with relations and relational operators is that equality is
> defined. (In PostgreSQL, there is an additional requirement that
> ordering is defined if you want to use indexing on those types, so we
> might have to put that down as a requirement too.)

Is this rephrase ok with you?

It is imperative for any practical solution (i.e. with indexing) that ordering operators (<, >) of a type can be communicated.

> However, there's a great big "!!!" sign on the road ahead; can you
> guess what it is yet ?

I am looking for them. Please share the one you see. Received on Sun Jun 04 2006 - 06:00:11 CDT

Original text of this message

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