Re: In an RDBMS, what does "Data" mean?

"x" <x-false_at_yahoo.com> wrote in message news:40cf3513_at_post.usenet.com...
> > > What is the difference between a simple, sound design of a star schema
> and
> > a
> > > fully normalized relational database ?
> >
> > Is this a rhetorical question or do you really want to know?
>
> I really want to know. (is this so strange ?)

OK. Sorry to be so difficult, but I've been burned more than once in this forum for giving a straightforward answer to a rhetorical or sarcastic question.

A star schema serves different purposes than a fully normalized design. Depending on what you are trying to do, it could be the right way to go, or it could be an unfortunate design decision.

A star schema is still in 1NF, so there's no issue there. Many of the dimension tables have a simple key, so they are automatically in 2NF. The fact tables typically aren't even in 2NF. But for 3NF and beyond, there is simply no attempt to normalize at all. You pay the price in redundancy, and you pay the price in difficulty to load.

But you gain enormous power and simplicity when you want to take the same data, and slice it and dice it every which way, or drill down for more detail, etc. etc. There is even a tool, from the vendor of SQR (I forget who) that does all kinds of OLAP games, but has no MDDB of it's own. Instead, you plug it into your star schema, and you're ready to rock and roll! Received on Tue Jun 15 2004 - 22:02:09 CEST