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

"x" <x-false_at_yahoo.com> wrote in message news:40cef875$1_at_post.usenet.com...
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> "Laconic2" <laconic2_at_comcast.net> wrote in message
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> > When I built a "data mart" in Oracle as a star schema, I included all
the
> > primary and foreign key constraints, even though it slowed down loading.
> > The advantage came when I went to copy the star into Cognos (Impromptu
or
> > Power Play, I forget)
> > Both Cognos and the Oracle optimizer recognized my star schema for what
it
> > was, and made appropriate use of that fact.
>
> You were lucky.

I don't think so. The engineers who built the CBO for Oracle were real smart. And they had the example of the DEC Rdb optimizer to guide them. And there was a note somewhere in the release notes saying they had implemented a thing they called a "star join". That was enough for me.

And the Oracle DBA, who had plenty of experience with databases that ran like molasses, was amazed at the performance I got out of this beast. Especially when she looked at my code, and didn't find any "hints" and already knew that my tablespaces had nothing but default parameter settings.

It's amazing how many times you "get lucky" by just following simple, sound design, and by keeping things "as simple as possible, but not simpler than that." In the few places where you end up with a performance problem, you can typically tune locally, without ripples spreading all over the system.

The engineers who built the Cognos data extraction tool were real smart. And if they knew MDDB down cold (which they must have), then they almost certainly knew how to recognize a star schema when they saw one. They way I knew that they knew was by looking at the SQL the Cognos tool used to extract the data from my star schema. Sure enough, they "got it".

A lot of people in this business get a lot of bang for the buck by assuming that "everybody but me is an idiot". I've gotten a lot of bang for the buck by assuming just the opposite: "nobody in this business is an idiot. But everybody makes mistakes, and some of them are idiotic."

(I occasionally call people "idiots". But that's just venting.) Received on Tue Jun 15 2004 - 17:23:56 CEST