Re: Mazes, trees, and forests
Date: Mon, 26 Apr 2004 14:23:44 +0300
Message-ID: <408cf090$1_at_post.usenet.com>
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"mAsterdam" <mAsterdam_at_vrijdag.org> wrote in message
news:4089a993$0$563$e4fe514c_at_news.xs4all.nl...
> x wrote:
>
> > Why do you consider only the foreign-keys of R1 ?
>
> Following the forestify algorithm eventually all foreign
> keys will get their turn.
Sorry. Why only the FOREIGN-KEYS and not ANY subset of attributes ?
> > A user can connect any two relations on any two attributes of compatible
> > types.
> Sure, and by expanding along those lines every user can
> build his own forest.
So there would be a forest for every user ?
> > Do you consider only the base relations or any relation ? ;-)
>
> Well, I did. With 'any relation': you mean every conceivable relation
> on a base?
"any relation" = base or derived relation
> > How can someone (other than the user) predict for what pairs of
attributes
> > the join of two relations make sense ?
>
> Why would anyone *want* to predict that? Sensible types help, but beyond
> that ... could you clarify how this impacts the suspicions I mentioned
> in the first posts?
Well, you said:
"This TELLS us something about wether and how much
of the data in the database can be expressed as
trees and THE LOSS we incur by doing so."
> > This is why a relational DBMS is different from other types of DBMSs.
>
> Do you mean to imply that with 'other types of DBMS' (historic I assume)
> can't connect as they please? I must be misreading you.
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