Background to dimensional modeling
When relational databases were introduced in the early 80s, businesses were promised that they would never lack information again. Slogans such as "information at your fingertips" and "always make decisions based on facts, not on gut feeling" were used to sell relational databases. These slogans are still used today. This time, they are used to sell business intelligence.
Gartner defines business intelligence as follows (www.gartner.com/it-glossary/business-intelligence-bi):
A more pragmatic formulation could be: provide the right people with the right information at the right time in the right format.
Using SQL, this promise seemed within reach. Using SQL, you can formulate any...
