Re: Nearest Common Ancestor Report (XDb1's $1000 Challenge)

> > Tony wrote: If your analogy holds any water at all (to give you the
> > benefit of very large doubt), it suggests that relational theory will do
> > just fine for pretty much anything we ever want to do "in the real world".

Relational may not be Turing Complete, but it does not have to be. Nor is it meant to be a "total solution". It is a very helpful tool that complements application code (and may even help organize it).

Relational may not do everything well, just an awful lot well. I do agree that it would be nice
if relational implementations had more
hierarchical operators, but in practice most classification systems are not really trees when they grow beyond the non-trivial. Trees have some nasty limitations, yet some people keep seeing them as a the Ultimate Structure. The real world is not tree-shaped for the most part. Philosophers have known this for a hundred+ years. Tree-like elements pop up, but there are usually enough exceptions to make a pure tree impracticle. It degenerates into a graph, and relational many-to-many tables are pretty good at that.

>
> $1000 to the first person who replicates the equivalent of
> www.xdb1.com/Example/Ex076.asp using the relational model. To claim
> the prize, one needs to produce the equivalent Nearest Common Ancestor
> Report from normalized and NULL-less data and the solution must be as
> generic, meaning allow the user to create any hierarchy, consisting of
> different types of things (each type to allow different attributes)
> and each thing in the hierarchy to have any number of parents. Report
> generation must not be more than 2X slower than XDb1 on equivalent
> hardware.

-T- Received on Mon May 17 2004 - 05:40:36 CEST