Re: Top Ten Errors In Data Wareousing

In article <3icume$ct3@mozo.cc.purdue.edu>, parmentr@prism.cc.purdue.edu wrote: > In article <3i8duh$86b@newsbf02.news.aol.com>, pineryjim@aol.com (PINERYJIM) says: > > >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 claim no particular expertise, but in my opinion a data warehouse > is a *new* thing. Regular databases are optimized for transaction > processing which implies a high proportion of "create or update" > activity and, we would hope, not a lot of full table scans and long- > running queries. A data warehouse is a repository for static data. > The tables may be updated monthly, weekly or daily, but not on-line. > Warehouse tables typically have lots of indexes and may be tuned to > accommodate the most frequent sorts of queries. Some folks even > recommend (horrors!) de-normalizing tables to the extent of, at > least, pre-joining lookup tables to create faster access at the > (to end-users) negligible cost of redundant data(!) in the warehouse. > > The really *new* thing is that warehoused data is intended to be > accessed by end-users so they can get the data themselves and use > desktop tools to turn the data into the information they need. > End-user empowerment -- what a concept! This thing could do away > with the typical MI application backlog (did I see 7 years cited > somewhere) if implemented properly. > > Bill Parmenter > Sr Software Engr > Purdue University As an add-on, Ken Orr, of The Ken Orr Institute recently redefined the goal of data warehousing as: "To provide any user access to quality enterprise-wide data" The recent definition incorporates the concept of quality, one of the most difficult aspects of effective warehousing. --------------------------------------------------------------------- Derek Cooper CompuServe Tel: 613-548-4355 Andyne Computing Limited ID: 72662,427 Fax: 613-548-7801 552 Princess Street FORUM: GO ANDYNE AppleLink: ANDYNE Kingston,Ontario,Canada K7L 1C7 http://www.andyne.on.ca/ ---------------------------------------------------------------------