Re: vehicle to autoparts relationships

Vadim Tropashko wrote:
> Aloha Kakuikanu wrote:

> > In this particular example we see that
> >
> > {112,114,194} <= {112,114,194,110,116}
> >
> > in other words, BOLT ASSEMBLY includes EXTRACTOR ASSEMBLY.
>
> "Find all the AssemblyParts that include EXTRACTOR ASSEMBLY" - a
> relational division query. It is essentially a hierarchical query
> "Find all the nodes ancestors"
> in this model.
>
> Who might have think that the two favorite Celko's topics are so
> closely related?

It is not surprising if you recall that that trees and powersets ordered by inclusion are closely related by both being posets, or alternatively a powerset ordered by inclusion is a tree. Received on Thu Nov 23 2006 - 19:36:35 CET