Joining fact tables?

From: Vikas Agnihotri <vikasa_at_writeme.com>
Date: Wed, 20 Oct 1999 14:20:12 GMT
Message-ID: <7ukj2e$75q$1@nnrp1.deja.com>

Transforming a complex OLTP system (400+ entities) into a DM model would lead to dozens (?) of dimension and facts.

Each fact table could contain information at a different "grain", different subject areas for exploration, etc.

Invariably, there would be a need to combine information from 2 fact tables, leading to a join between 2 fact tables and the related dimension tables.

Is this a Good Thing? Seems like fact tables are not meant to be joined to anything but their corresponding dimension tables.

Wouldnt joining 2 fact tables lead to horrible performance and violate the basic point of doing DM?

Any comments, experiences appreciated.

Thanks,
Vikas

P.S: Realistically speaking, what is the maximum number of dimension tables that one could have in a "star" schema? 10, 20, ...?

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Before you buy. Received on Wed Oct 20 1999 - 09:20:12 CDT