Advanced Cube Design - Professional SQL Server Analysis Services 2005 with MDX - page 384

Figure 9-2
IgnoreUnrelatedDimensions is a new property that provides the functionality
of the ValidMeasure MDX function, often used when working with virtual
cubes in Analysis Services 2000. A virtual cube, you may recall, simulates the
consolidation of multiple fact tables within a single cube. The ValidMeasure
function returns a cell value corresponding to the All member for a dimension
that does not have a relationship with the current measure. In other words,
the dimension is not represented by a foreign key column in the fact table
containing the current measure.
To continue the previous example, with the IgnoreUnrelatedDimensions prop-
erty for the Internet Sales measure group set to False, you can execute the
following MDX query to see that the cell values for all the members in
Reseller Type hierarchy have the same value for measure x, while the real
measure Internet Extended Amount has null values:
WITH MEMBER measures.x AS Validmeasure
(([Measures].[Internet Extended Amount],
[Reseller].[Reseller Type]))
SELECT { measures.x,[Measures].[Internet Extended
Amount]} ON 0,
[Reseller].[Reseller Type].members ON 1
FROM [Adventure Works]
Another important measure property to know about is MeasureExpression.
On the Cube Structure tab of the cube designer, click the Internet Sales
Amount measure in the Internet Sales measure group to see its properties, as
shown in Figure 9-3 . A valid value for MeasureExpression is an MDX expres-
sion that typically includes product (multiplication operator) or ratio (division
operator) of two measures (or constant). This type of expression is used for
currency conversions or when aggregating values with many-to-many dimen-
sions, which are both discussed later in this chapter. When you specify a
measure expression, Analysis Services 2005 evaluates the expression for
each dimension member first and then aggregates the values across the di-
mension.