Why do all my 'Sum of Units' rows all have the same values in PowerPivot?

Question

I'm pretty new to PowerPivot and have a problem.

I created an SSIS project (.dtsx) to import around 10 million rows of data and an Analysis Services Tabular Project (.bim) to process the data model.

Up until today, everything worked as expected, but after making a schema change to add further columns to a table and updating the model, I now have a problem. When opening the existing connection in Business Intelligence Development Studio (BIDS) to update the schema changes, I was told that I would have to drop and reload the Sales and Returns tables as they were related.

Now, when I try to filter on a particular attribute, the Sales 'Sum of Units' column always displays the total sum of units for every row, instead of the correct values. I remember having this problem once when I was building the system, but it went away after re-processing the tables in BIDS... this time however, no amount of processing is making any difference.

I'm really hoping that this is a common problem and that someone has a nice easy solution for me, but I'll take whatever I can get at this stage. I'd also quite like to understand what is causing this. Many thanks in advance.

Answer 1

For anyone with a similar problem, I found the answer.

Basically, I had made a schema change and BIDS told me that I had to drop my SalesFact and ReturnsFact tables before updating the model with the new database schema. The problem was that I did not realise that relationships had been set up on these tables and so after re-adding them, the model was missing its relationships to the other tables... that's why all rows showed the same value.

The fix was to put the model into design view and to create relationships between the tables by clicking and dragging between them.

I knew it was something simple.