Introduction to MDX - Professional SQL Server Analysis Services 2005 with MDX - page 95

Notice that there are no square brackets in the expression for the member
Australia. This is due to the fact that Australia is one word and no numbers
are involved. In general, you can use the following format for accessing a
member.
[DimensionName].[HierarchyName].[LevelName].[MemberName]
The above format is predominantly used in this chapter as well as the topic. If
you are developing client tools we recommend you make an effort to under-
stand the unique name algorithm from product documentation based on the
properties set for dimensions. In this way, you can use the best name format
to access a member.
Cells
In Figure 3-2 you can see three faces of the cube. You can see the front face
of the cube has been divided into 16 small squares, and each square holds a
number. The number represented within each square is the measure "Internet
Sales Amount" of the AdventureWorksDW cube. If you view the remaining
visible faces of the cube you will realize that each square you analyzed in the
front face of the cube is actually a small cube. The top-right corner square of
the front face contains the value 1134; you will notice that the same number is
represented on the other sides as well. This smaller cube is referred to as a
cell.
The cell is an entity from which you can retrieve data that is pertinent to an in-
tersection of the dimension members. The number of cells within a cube de-
pends on the number of hierarchies within each dimension of a cube and the
number of members in each hierarchy. As you can imagine, cells hold the
data values of all measures in a cube. If the data value for a measure within a
cell is not available, the corresponding measure value is a Null value.
If you are familiar with three-dimensional coordinate geometry you are aware
of the three axes X, Y, and Z. Each point in three-dimensional coordinate geo-
metry is represented by an X, Y, and Z coordinate value. Similarly, each cell
within a cube is represented by dimension members. In the illustration shown
in Figure 3-4 , you can see the three dimensions: Product, Customer, and
Date. Assume that each of these dimensions had exactly one hierarchy that
is illustrated in the figure, namely, Product Line, Country, and Calendar Time.