Saturday, February 13, 2016

Data Warehouse models–comparing Kimball to Inmon

Have recently seen various folks whiteboarding approaches to data warehouse (enterprise data, data stores, ods, etc.) One thing I’m noticing is that they generally fit one or both of the historically accepted approaches, those proffered by Ralph Kimball (and group) and from the writings of Bill Inmon. 

Here’s a comparison diagram I have referenced many times over the years.  The diagram, and article, is from 2010, but the original thought dates back to the 1990’s or earlier.

https://bennyaustin.files.wordpress.com/2010/05/kimball-vs-inmon4.jpg

https://bennyaustin.wordpress.com/2010/05/02/kimball-and-inmon-dw-models/

Take them for what they’re worth and for the era they come from.  Inmon’s model contains what looks like the current buzzword of ‘data lake’ (though Gartner and others are skeptical of the approach)  In all practicality, the only OLAP cubes developed today against a star schema layer.   Agile tools like PowerPivot and Tableau bypass this somewhat, but still contain a step where one models groupings (i.e. dims) and aggregate (i.e. facts)