in business intelligence (BI) and data warehousing (DW) projects are
very familiar with terms such as facts, dimensions, attributes,
surrogate keys and slowly changing dimensions. But knowing the terms is
not enough. Increasingly, there appears to be a significant disconnect
between how BI or DW systems are actually built versus the best
practices described in books and articles. Clients point out that the
concepts in some books and articles are esoteric because they are not
connected to real-life situations. They teach the how but not the why.
Two best practices that people think they are implementing but often
fall short of are dimensional modeling and the hub-and-spoke
When you don’t know why you should design a DW a certain way,
it’s easy to make the common mistake of designing DW and BI systems to
look like your source systems.