This is because dimensions cannot be used in calculations when using a cube as a data source. However, dimensions can be converted into measures by creating a calculated member. An example calculated member would be the following:
(DateMember is defining Orders, and Member Values is defining Order Priority).
Hope this helps!
Thanks for the reply Tracy!
The primary data source for my report is the cube. I am attempting to filter the results from the cube based on attributes stored in the relational data. Each exposes an identifier that can be used to join them.
The relational database exposes a view with an EntityId and two dates. The cube also exposes the EntityId, and the financial information is all date-based. If the data in the cube for a specific EntityId does not fall between the dates specified by the relational view, the data is to be excluded from the report.
You can only filter on the primary source.
When working with a primary and a secondary data source then you has to keep in mind that your secondary data source is for looking up information (like Excel vlookup-function).