Extending MDX using External Functions - Professional SQL Server Analysis Services 2005 with MDX - page 489

Profit Cum Profit

2001 1,576,032.17 1576032.1682

2002 2,705,927.15 4281959.3152

2003 − 168,557.73 4113401.5814

2004 − 13,288.53 4100112.0547

Analysis Services calls the UDF for each member of the ship date to calculate
the cumulative sum up to that year, thereby resulting in calculating the cumu-
lative profit for each year. In this query the UDF is called four times because
there are four members returned in the result.

Disambiguating Between Functions

You can add multiple COM UDFs that contain the same function names to a
database or Analysis Services instance. If you have more than one function
with the same name within Analysis Services, any query using the function
name will result in an error. This is due to the inability to resolve to the correct
function name. In such a circumstance you can explicitly specify the fully
qualified name of the function by pre-pending it with the classID of the library.
The classID of a function looks like this: AssemblyName.ClassName . If you
have created your UDF using a Visual Basic project that contains a package
name called COMExample and a class name COMExampleClass , you need
to access the function as COMExample!_COMExampleClass .Function.