Complex Calculations

Question

Hello,
I need to create a calculated measure that is the sum of five fields. I know I can do this by creating three intermediate variables (due to the limitation of only being able to add two numbers together in the standard calculated measures), but is their a better way to do this? I would rather not have a bunch of intermediate measure clogging up what the users see in Discoverer.
Any help would be greatly appreciated.
Thanks,
Carl

Answer 1

You have probably noted that the Calculation Wizard in Analytic Workspace Manager does not offer free from calculations such as Measure_A = Measure_B + Measure_C + Measure_D + Measure_E + Measure F. You have two other methods that you can define calculation: altering the formula of a measure using the OLAP DML and adding the measure through the AW/XML API.
The OLAP DML is the language of the multidimensional engine. The method of using this language to change the equation of a formula is as follows:
1. Create a calculated measure (any calculation) in the appropriate cube.
2. Change the equation using the CONSIDER and EQ commands. Let's say you created the TOTAL_SALES measure in cube UNITS and you want this to be the sum of several other measures. You would using the following command in OLAP Worksheet (which is accessed via AWM's Tools menu).
CONSIDER UNITS_CUBE_TOTAL_SALES
EQ UNITS_CUBE_SALES_B + UNITS_CUBE_SALES_C + UNITS_CUBE_SALES_D + UNITS_CUBE_SALES_E + UNITS_CUBE_SALES_F
UPDATE
COMMIT
Note that the measures are all referenced by their formulas (rather than the variables) in the above example.
To view the altered formula, use the DESCRIBE command. E.g.,
DESCRIBE UNITS_CUBE__TOTAL_SALES
This method is pretty easy. The downside is that the equation does not get carried with any templates you create of the measure, cube or AW. Also, if the physical implementation of the AW (that is, the low level objects that make up the phyiscal model) change, you might need to revisit the measure and make adjustements. Neither of this issues are a big deal - you just need to be aware of tthem.
The other approach is to create an AW/XML template and read it using AWMs Create Custom Measure from Template command (right mouse of Calculated Meaures under cube). A sample follows.
<Create Id="Action1">
<ActiveObject >
<DerivedMeasure Name="TOTAL_SALES" LongName="Total Sales" ShortName="Total Sales" PluralName="Total Sales" Id="UNITS_CUBE.TOTAL_SALES.MEASURE" DataType="decimal" isInternal="false" UseGlobalIndex="false" ForceCalc="false" ForceOrder="false" SparseType="STANDARD" AutoSolve="DEFAULT" ExpressionText="UNITS_CUBE.SALES_B.MEASURE + UNITS_CUBE.SALES_C.MEASURE + UNITS_CUBE.SALES_D.MEASURE + UNITS_CUBE.SALES_E.MEASURE + UNITS_CUBE.SALES_F.MEASURE"/>
</ActiveObject>
</Create>
Note that in the AW/XML XML document all objects are reference to by their logical names.
The advantage to this approach is that the AW/XML api is fully aware of the measure definition and (a) can carry it in AW, cube and measure templates and (b) it insulates you from the physical implementation.
If you try this approach, be aware that the syntax is exacting and that error messages from bad syntax is not easy to interpret.