How many columns does the largest table you've ever worked with contain? The current project I'm working on has 1 table with almost 2000 columns (and it's likely to add more!). This is the most highly denormalized design I've ever encountered and there's something about it that makes the performance optimizer in me cringe. But, the statisticians that have to munch and crunch this data in SAS tell me this format best suits their needs (based on similar designs used successfully in previous projects).
I think I'm really more concerned about the work that has to be done to populate these columns as most of the columns contain aggregations or formulations of some sort or another. So, perhaps it's not the number of columns that really is niggling at me as it is everything that must occur to produce the values contained in a single row (it's a lot).
What's your experience? Did the number of columns help, hinder or make no difference in the design and performance of the application that used such wide tables? This phase of the project is a proof of concept so it'll be a while before I get hard data on how well (or not) this design really works, but it has certainly made me curious about what other folks have experienced.
Let me hear from you if you have any comments or insights!