In SSAS I am trying to model the following relationships:
Response -> DataPoint (Many to One)
DataPoint -> DPYearAquired (one to one)
There can be zero or one rows in DPYearAquired for each row in DataPoint.
I've created a dimension called DataPoint based on the DataPoint table, and added an attribute based on the Year column in table DPYearAquired. I've also set NullProcessing to UnknownMember for the attribute. However when I process the related cube, I get the error "The attribute key cannot be found when processing ... The attribute key was converted to an unknown member because the attribute key was not found". It is perfectly valid for there to be no row in DPYearAquired for a DataPoint. I am not sure what the best way to model this is.
Any help is much appreciated.