OracleBIBlog Search

Saturday, November 28, 2009

Kimball vs. Inmon: The TDWI perspective

Surfing through the blog posts trying to be "inspired", I stumbled upon a year old post comparing Kimball and Inmon's architecture. I learned about the differences between their architectures during my courses at the TDWI conference. Only having read Kimball's literature, I was intrigued by this rivalry.

As it was explained to me, Kimball's "Bus Architecture" defines a data warehouse as the combination of all the data marts, which would make the data warehouse responsible for the intake, integration, distribution, delivery, and access of data. Comparatively, Inmon's "Hub and Spoke Architecture" defines the data warehouse as "a subject-oriented, integrated, non-volatile, time-variant collection of data organized to support management needs." Basically, it is responsible for the intake, integration, and distribution of the data. The argument proposed in the course was which was better to use?

To me, it seems this depends on the level of the BI program at the business in question. Is your business new to BI or finding their previous BI project poorly integrated? You could do well to subscribe to Kimball's approach, as it quickly allows the users to get what they need. However, as the BI program matures and more data marts are developed the issue of maintaining the "bus," the rules that define the conformed dimensions necessary for the architecture, become harder to keep aligned. This is where Inmon's approach makes sense, by pushing the conformity back to the warehouse, it is easier to administrate changes to rules and enforce integrity.

True, the line where it makes sense to implement the "hub" in the Inmon's architecture is hard to draw, but aside from that blurred area, I'm not sure there is much to arguing one as "better" than the other. To me it's simply a matter of BI Program Maturity.