I had the privilege of spending three days at The Data Warehousing Institute‘s (TDWI) 2008 World Conference in Las Vegas this week. The event runs Sunday to Friday; I attended Monday to Wednesday. TDWI puts on a first-class event. The main reason I went and what I most enjoyed about the three days was the opportunity to learn from experts in the courses that were offered.Each day I went to a day-long data modeling course: the first two courses were more high-level, basic courses–one on modeling, one on dimensional modeling–taught by consultant and author Steve Hoberman; a more advanced dimensional modeling course was taught by Laura Reeves, principal at StarSoft Solutions and co-author of The Data Warehouse Lifecycle Toolkit. Steve and Laura both have over 20 years experience as data modeling practitioners.
Monday’s class, TDWI Data Modeling: Data Analysis and Design for BI (Business Intelligence) and Data Warehousing Systems, was a great primer for the classes that followed. It was mostly conceptual, and provided a framework from which we could dive into more practical topics later in the week. Steve repeatedly stated that with enough time and money we have the ability to model anything, including world peace. We went through the progression of modeling, from contextual to conceptual to logical to structural to physical. The time we spent discussing the differences between dimensional modeling and relational modeling was helpful. It has been my experience that it is difficult to satisfy a business unit’s requirements by implementing a purely dimensional model: there is usually some need to replace a list that is generated by whatever current system we’re replacing. Steve acknowledged that most marts are indeed hybrids and that there is usually cause to break the ‘rules’ of modeling to meet a business need.
Tuesday’s class, TDWI Dimensional Data Modeling Primer: From Requirements to Business Analytics, was very practical. It presented a specific methodology to follow to build a dimensional data mart. The main takeaway for me was the necessity to spend time probing the business and logically modeling a solution before moving into the physical. My tendency is to let the business work out the requirements with a business analyst from IT who translates the requirements and then to prototype solutions and then iteratively improve it until the business is satisfied. Handing off the dirty, not so fun requirement gathering work is very tempting but not a good habit. I am currently taking an MBA course called Software Requirements Management and it is only reinforcing my distaste for the whole process. Conversely, Tuesday’s course underpinned the value of asking why questions and of truly understanding what is trying to be accomplished rather than simply what the requirements are.
The final class I attended, Dimensional Modeling beyond the Basics: Intermediate and Advanced Techniques, was very practical. The course instructor, Laura Reeves, repeatedly emphasized that modeling is an art and there is no one right answer. If something works, it works. There was a ton of experienced technologists in the room, many who wanted free consulting from a subject-matter expert. The topics covered–Multiple Roles, Complex Hierarchies, Date and Time, Many-to-Many Relationships, Fact Table Design, and Aggregation–are all stumbling blocks modelers seem to encounter on even the most straight-forward projects. Laura drew on a bevy of experience and was willing though sometimes embarrassed to share the dirty tricks she’s used to implement a solution. I was at least nominally familiar with most of the concepts presented because she is a co-author of the reference book I use when faced with challenges.
The three days were extremely draining. In the evenings when the vendors were putting on ‘exhibits’ with free booze, go-go dancers, Elvis and Mike Myers look-a-likes, all I wanted to do was sit in front of the television and zone out. TDWI does a wonderful job ensuring that the courses are sales-pitch free and that the vendors are separated from the educational area. If you want to speak with vendors, there is ample opportunity. Equally comforting is the ability to avoid them altogether. I spent some time watching new product demos and reading the latest literature, but steered clear of whoring my contact information in order to enter contests for gift cards and cool electronics. My favorite contest was for the Sony Wii: I wonder what Nintendo thinks about that.
Now it is back to reality, back to the grind. Armed with my new knowledge I can surely do some damage.