what-if analysis on Rolap Or Molap & how?

Question

i would like to simulate what-if analysis on a OLAP cube For example, i would like to know the impact on departmental resource budgets by moving employees between departments or the movement in cost of manufacture if a product is moved from one factory to another.

so should i use an rolap cube'mondrian' or molap ?

i will greatful if you can give me some exemple , tuto ... ;) thank you in advance

Answer 1

I would say that Mondrian is an engine to query an existing database that is has a dedicated structure for Olap (usually some kind of star schema).

It is definitely not something to manipulate (or even) change data. Since each what-if analysis needs to change data in some way or another, Mondrian is not the tool for it.

Answer 2

Actually mondrian does support "writeback" (via olap4j) so you can do what if analysis. Check out Saiku - AFAIK it's the first and only tool to have implemented it so far.

Here is how it works - it's pretty rudimentary:

http://julianhyde.blogspot.co.uk/2009/06/cell-writeback-in-mondrian.html

Martin is close to the point though, it doesn't actually update the raw data, only objects in the cache. But you wouldnt want to update raw data if you were doing what if analysis anyway!