This week I had the pleasure to attend the Kimball Group course “Dimensional Modeling in Depth” in Amsterdam. The course was given by Ralph Kimball and Margy Ross, the authors of the book “The Data Warehouse Toolkit” and many other publications of Kimball Group.
Most people working with Data Warehouses and dimensional data models know Kimball’s books – or have them at least in their bookshelf – and use the standard concepts like Conformed Dimensions or Slowly Changing Dimensions in their daily DWH life.
“If you do dimensional modeling since years, it does not mean that you do it right since years“. This was the introduction of Margy Ross at the beginning of the course – and for me a very important statement. I think I am familiar with dimensional modeling, but I was a bit unsettled what to expect to hear from the experts in the course.
Clear explanations of dimensional concepts
The first two days were given by Margy Ross. She explained the fundamental concepts of dimensional modeling in clear and exciting lessons. Most of the things she talked about were not new to me (if that would be the case, I would have the wrong job). But there were several aspects and details that I wasn’t aware of or that I never used until now. Especially the group workshops were really helpful to find out that the design of a star schema is not always as easy as it looks at the first glance. Margy is an excellent teacher who knows how to explain complex subjects in a clear manner.
Dimensional specialities and entertaining stories
The 3rd and 4th day, Ralph Kimball talked about advanced dimensional techniques and some “exotic” concepts. Many of his examples were based on real-life projects. Because some of them were rather complex case studies, it was sometimes hard to follow his explanations. But it was very interesting to learn how dimensional modeling can be used in complex business cases and how the fundamental concepts can be adapted to special requirements. Additionally, it was a pleasure to listen to the presentation. Ralph Kimball is a good storyteller with a great sense of humor.
Was it worth to attend the course for me?
Yes, absolutely! Although I work with dimensional data models since years, I learned a lot of additional details about Outriggers, Hierarchical Bridge Tables, Accumulating Snapshot Facts, Ragged Hierarchies, Multi-valued Dimensions, Compliance Tracking and much more. I guess that I can use some of these concepts in customer projects, and I also have some ideas for presentations and articles. Even if dimensional modeling is in use since years, it is still an interesting topic to learn new things.