Re: Lucid statement of the MV vs RM position?

dawn wrote:
> Jan Hidders wrote:
> > dawn wrote:
> > >
> > > My goals would still include getting the word out about this fatality.
> > > I doubt many undergraduate courses teach that 1NF, as we knew it, is
> > > dead, for example. I sure don't see that knowledge having made it into
> > > the practitioners "common knowledge" as yet.
> >
> > It shouldn't.
>
> Yes, it should. Should all XML documents be in 1NF? If not, why not?

That is neither here nor there. The question is not if you should always model your data such that it is in 1NF.

> > Finally, whether using
> > nested relations / lists is in practice a good idea depends on how
> > efficiently your DBMS supports them
>
> Agreed.
>
> > and for example can do decent query
> > optimization on them. AFAIK the jury is still out on that one,
>
> Well, there's more than 30 years of production apps out there running
> flavors of MUMPS, PICK, and others from which the jury could gather
> data.

They already have done so, and they already know why they work efficiently under certain circumstances, and under which circumstances they have problems.

> Even if you don't like the lack of DBMS-defined constraints on
> the way in, those are not required for determining read-only query
> performance. Unfortunately, there are no industry performance measures
> of which I am aware that are not designed strictly for SQL-DBMS's (or
> do you know of some?)

Simply translate they SQL queries to queries in the ad-hoc query language of your favorite system. Presuming, of course, that this ad-hoc query language is powerful enough. Any extra required programming would of course make the comparison meaningless.

• Jan Hidders