Table DimProject has 2 mappings, each from a different source:
Mapping 1 = SourceA.Project
Mapping 2 = SourceB.Project
Now both systems will have the same project number with different meanings.
My question is how do I make a transformation that returns 'A' + [project number] in mapping 1 and 'B' + [project number] in mapping 2.
The solution needs be rely on explicitly meaningful conditions, no implicit conditions that drive people crazy trying to decipher what they are for somewhere in the future.