the entire world is not a single cube....(or why i won't let them talk me into putting 20 dimensions on one cube)
Business process analysis. Definitely needed before building multidimensional database objects. The problem i've had on the project i'm working on now is a lack of that knowlege on the user's part. They don't know what they need so they think they need EVERYTHING. Problem is, using MOLAP storage, hanging more than 15 dimensions on a large fact table makes it like--SLOW. Haven't tried making large lummoxes using ROLAP or HOLAP, so can't tell you how that would perform.
Techies gotta sometimes play business analyst. So last pass, i built them four cubes out of the same data and did some guesswork on logical reporting and analysis needs. Built one cube just for reports, and one just for analysis. Different ways of looking at the data. Had the last two cubes built along related-data rules. For example, one cube was all about financial-related stuff, and another about human resource-related stuff. So basically i said, 'yes you can have the 20 different slicers and you can mix and match them, but you can't have all 20 of them at once.' I put these cubes on the test database and let them have it, in a week or so of banging on them, we will all have a better idea what everybody needs/wants/wishes to have.
So far they love the technology. I keep hearing things like 'wow--this takes me 5 minutes in Excel to put together something that took me 4 hours with regular query tool stuff'.
The other big data problem is the wish list. There is this wish to see this data sliced in a way that is not easily extracted out of the system. Sometimes, this is based on someone's spreadsheet where they do all this by hand, or even an Access database. If they can manage to show me their rules and I can automate them, we are in business, but sometimes, you just can't split the data the way they want because the information in the source data just isn't that flexible. This can lead to frowns. Users always know what they don't have, but hey--sometimes miracles happen right? If i manage to pull off 'spreadsheet slicher # 45' i have an extremely happy camper. For now. hehehe
l8r,
--deb