How to determine level keys for a hierarchy in Cubing services

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Problem
Before deploying a cube into cube server , we need to Brower the cube in design studio to make sure that cube is validated and can be processed. One of main errors is that one and more hierarchy can’t be loaded.
 Searching the key words “This requires a fix to the model” or “Thrown stack trace” , you will find error as follows:
“Duplicate member key values for different level keys may occur if an insufficient number of level key columns are defined in each level during modeling. This requires a fix to the model”
 
 

Solution

To make a level key “unique”, meaning that there should NOT be one child at this level with multiple parents. For example, if you define Month name as month level key, it can’t be processed as month January can be under any years (2010, 2009). What we need to do is to add year as level key, together with month name as combined level keys. If it is the lowest level, make it absolutely unique across the whole dimension.
If a level key is not “unique”, it is still valid for Cognos framework manager and SSAS, but it is NOT valid for cubing services. The IBM cubing services requires much more strict and rigorous. Therefore, we can’t define cube mode by exactly coping Cognos FM model.