Re[2]: Top Ten Errors In Data Wareousing

>Now that we apparently have an institute dedicated to the practice of data >warehousing I'm wondering if the term also has an institutionalized >definition. Just what is it you do when you warehouse data? Or, from a >different perspective, what kind of data does a warehouse contain? Or, am >I missing the point altogether? I saw an article once that explained "data warehousing" as "designing a system to support the "query from hell". As others have stated, this would be a quasi-static system, that is updated from the TPS side and provides "pre-digested" data to the end-user. The warehouse would be optimized for query (user access), instead of rapid update/deletes. It seems to me that a significant amount of analysis work would be needed on the TPS side to ensure that data that is summarized on the warehouse side, is not updated on the TPS side at a later date. Is this correct? In a previous job, we looked at this "functionality". However we ran into the problem of "gee, we really need to update the data from two years ago" We now need to re-run all the monthly reports for the previous two-years, and store the new numbers in the warehouse. Since this was a common occurrence, (on a newly deployed system), and the reprocessing of reports would significantly affect the production times, we decided to wait until the data was more "stable". Greg