To DM or not to DM...that is the question?

If this is not the appropriate forum, please point me to it.

Just ran into Rob Armstrong's rather interesting rebuttal to Ralph Kimball's "Dimensional Modelling manifesto". A few questions about it...

First of all, the rebuttal is bit dated (1997). Does it still hold?

If so, then here goes:

My company (division, really) is just embarking on its "data warehouse" project. We have a rather complex OLTP system spanning the globe using Oracle, DCE, workflow management and a host of other sophisticated technologies. It automates most of the business processes involved in the transaction, flag errors, print customer correspondence, interface with the General Ledger, Accounting systems, etc. Very complicated.

The database used is Oracle. Just to give you an idea, it currently has around 400+ tables.

Needless to say, it is modelled in the Third Normal Form. The resulting ER diagram is monstrous.

Also needless to say, there is a mind-numbing amount of information stored in the system. Right now, the only reports it generates are end-of-day kind of operational reports, interfaces to other systems, etc. No broad-based "tell me how many ..." kind of questions.

The purported aim of the DW effort is to attempt to access and analyze that information to provide "business intelligence", discover relations in the data, etc. The usual stuff.

Given all this, we are having a hard time with the dimensional modelling. We cant figure out the facts and dimensions. We want access to the most detailed data, but at the same time, be able to see the forest and not the trees!

Is DM the right approach here? If not, how do we glean information from the monstrous OLTP system? Just saying "Use the right tools" is too naive.

Given that Rob works for NCR, I would understand his proclivity towards Teradata et.al, but I would appreciate an objective opinion of Oracle as the database.

If we were to stay with the TNF, which tools would you recommend to best navigate/extract the information? Manage metadata so that the users are shieleded from the complexity?

Thank you,
Vikas

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Share what you know. Learn what you don't. Received on Fri Aug 20 1999 - 09:55:22 CDT