Re: Mazes, trees, and forests
Date: Fri, 23 Apr 2004 11:56:58 +0300
- Post for FREE via your newsreader at post.usenet.com ****
"mAsterdam" <mAsterdam_at_vrijdag.org> wrote in message
> Mazes, trees, and forests.
> Say we have a populated database. For the ease of
> discussion let's assume it is a relational database.
> A2. Walk up from R1 along the foreign-keys of R1 to R2.
> Take the first candidate R2 to be the biggest relation
> to which an FK in R1 refers.
> Etcetera until we have a relation with no foreign keys.
> This gives us candidate tree Tree(R1,1).
> Repeat A2 until we walked all trees.
> Delete all population in the biggest tree from the
Why do you consider only the foreign-keys of R1 ?
A user can connect any two relations on any two attributes of compatible
Do you consider only the base relations or any relation ? ;-) How can someone (other than the user) predict for what pairs of attributes the join of two relations make sense ?
This is why a relational DBMS is different from other types of DBMSs.
- Usenet.com - The #1 Usenet Newsgroup Service on The Planet! *** http://www.usenet.com Unlimited Download - 19 Seperate Servers - 90,000 groups - Uncensored -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=