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

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"Laconic2" <laconic2_at_comcast.net> wrote in message news:bKWdnZSDTJWsiVLdRVn-jw_at_comcast.com...
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> "x" <x-false_at_yahoo.com> wrote in message
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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.

> The engineers who built the Cognos data extraction tool were real smart.

I did not thought otherwise.

> 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.

What is the difference between a simple, sound design of a star schema and a fully normalized relational database ?

> 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".

They "got it" because there was a "hint" somewhere. After all, you designed a "star schema". You were lucky.

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