Designing the Data Warehouse for Analysis Services - Expert Cube Development with SSAS Multidimensional Models - page 4

There are at least two major approaches to data warehouse design and development
and consequently, to the definition of what a data warehouse is. They are described
in the topics of the following two leading authors:

• Ralph Kimball : If we are building a Kimball data warehouse, we build fact

tables and dimension tables structured as data marts. We will end up with a
data warehouse composed of the sum of all the data marts.

• Bill Inmon : If our choice is that of an Inmon data warehouse, then we design

a (somewhat normalized) physical relational database that will hold the data
warehouse. Afterwards, we produce departmental data marts with their star
schemas populated from that relational database.

If this were a topic about data warehouse methodology, then we could write
hundreds of pages about this topic, but luckily for the reader, the detailed differences
between the Inmon and Kimball methodologies are out of the scope of this topic.
Readers can find out more about these methodologies in Building the Data Warehouse
by Bill Inmon and The Data Warehouse Toolkit by Ralph Kimball. Both books should
be present on any BI developer's bookshelf.

A picture is worth a thousand words when trying to describe the differences
between the two approaches. In Kimball's bus architecture, data flows from
the OLTP through to the data marts, as shown in the following diagram:

OLTPSystem(s)

OLAP

Data mart

Data mart

OLAP