Q: Analysis Services Cube Design

I have a (hopefully typical) problem when it comes to cube design. We
store millions of product records every year, broken down by
month/quarter. Each product can be assigned to various heirarchial
classification groups etc. The data in an OLTP DB occupies roughly
100G for a typical year.

We're looking at breaking this out into OLAP to provide faster access
to the data in various configurations and groupings. This is not a
problem, as this is the intended use for Analysis Services.

The problem is that we apply projection factors on the product prices
and quantities. This would be ok if it only happened once, however,
this happens every quarter (don't ask why). The projection factors
change 4 times a year, and they affect all historical product records.

This presents a challenge because to aggregate the data into a useful
configuration in the cubes, you throw out the detail data, but this
means throwing out the price and quantities which are needed to apply
the projection.

So if you have Product A at $10 and Product B at $20, and roll both up
into Category X, you'll have $30, but you'll lose the ability to apply
a projection factor of .5 to Product A and .78 to Product B. They're
rolled up.

I don't want to regenerate the cubes every 3 months. That's absurd.
But we can't live without the ability of projection the
prices/quantities on a product level (detail level). So how can this
be achieved when the other cubes are created at a higher level with
less details and sums of the detail data?

My initial guess is that we have to update the product data, and then
reaggregate all the other data that is built upon that product data.
Is there any other way to apply math to the data on the way out?

Thanks in advance!

Regards,

Zach