To do a join you usually need a PK and FK. Those need to come from the source.
Even if it is not an ID column it needs to be something that says this row belong to that rows in the other source/table.
I have two sources (that I am currently working on) that do not naturally have Key relationship but they deal with the same data just in a different fashion.
if no keys the look for person name, car make and model, flavor of soda and serving size, not sure what you data is but if you are trying to join it certainly they are related in some way.
Let explain mine a little more.
We have a lot of SSIS packages doing a lot of ETL. and we use Bi Xpress to do some monitoring of what is running did it finish and how long it took how many rows got read and insterted, excetra.
We also want to graph the system agent job information as well, for the ones that run these SSIS packages.
Now I created a view made up of the system tables data I want to graph and I have a query to the Bi Xpress table for the data we want to graph.
But there no natural key bewteen these two sources because well one does not really care about.
I had to find data that was the same in both sources to be able to join them.
I found that in some form in both sources there was the name of the SSIS package, but it was not that easy. In one table the package name was in the middle of a varchar so ai had to extract it to a new column. This is what I will use to join them.
You should not just add a column with made up numbers to both table to join them, doing that does not match rows that belong together.
You can Join in the Data Cube, but there is nothing in there that will help you find what to join on and making something just seams like the wrong way to go.
Go back to the data and see if there anything that can be used to match the orws up. if you need to combine a few things together or extract one part out of one, all that can be done in the Data Cube with calulated element.