Introduction to MDX - Professional SQL Server Analysis Services 2005 with MDX - page 91

Fundamental Concepts
The cube is the foundation of a multidimensional database. Each cube typic-
ally contains more than two dimensions. The Adventure Works cube in the
sample database contains 21 dimensions. The Adventure Works sample pro-
ject and relational database need to be selected explicitly during installation
from Documents, Samples, and Sample Databases. Using BIDS open the
sample Adventure Works project from Program Files\Microsoft SQL Serv-
er\90\Tools\Samples\AdventureWorks Analysis Services Project\Enterprise
and deploy it to your Analysis Services instance. If you open the Adventure
Works cube in BIDS you can see the measures and dimensions that make up
the Adventure Works cube in the Cube Structure tab as shown in Figure 3-1 .
Figure 3-1
The Measures object is basically a special dimension of the cube which is a
collection of measures. Measures are quantitative entities which are used for
analysis. Each measure is part of an entity called a measure group. Measure
Groups are collections of related measures and each measure can only be
part of a single measure group. Often you will want to have one measure
group for each fact table in your data warehouse. Measure groups are primar-
ily used for navigational purposes by design tools or client tools to have better
readability or ease of use for end users. They are never used in MDX queries
while querying measures. However, they can be used in certain MDX functions
which, by the way, you will see in this chapter and in Chapter 7 . By default