Expert Cube Development with Microsoft SQL Server 2008

OLTP System(s)
Data
Warehouse
[ 11 ]
Datamart
Datamart
OLAP
OLAP
Chapter 1
What is important is to understand is that the simple phrase "data warehouse" has
different meanings in each of these methodologies.
We will adopt Inmon's meaning for the term "data warehouse". This is because in
Inmon's methodology the data warehouse is a real database, while in Kimball's
view the data warehouse is composed of integrated data marts. For the purposes
of this chapter, though, what is really important is the difference between the data
warehouse and the data mart, which should be the source for our cube.
The data mart
Whether you are using the Kimball or Inmon methodology, the front-end database
just before the Analysis Services cube should be a data mart. A data mart is a
database that is modeled according to the rules of Kimball's dimensional modeling
methodology, and is composed of fact tables and dimension tables.
As a result we'll spend a lot of time discussing data mart structure in the rest of this
chapter. However, you will not learn how to build and populate a data mart from
reading this chapter; the books by Kimball and Inmon we've already cited do a much
better job than we ever could.
Data modeling for Analysis Services
If you are reading this book, it means you are using Analysis Services and so you
will need to design your data marts with specific features of Analysis Services in
mind. This does not mean you should completely ignore the basic theory of data
warehouse design and dimensional modeling but, instead, adapt the theory to
the practical needs of the product you are going to use as the main interface for
querying the data.
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