Re: DATA WAREHOUSING...

From: Don Berryman <berryman_at_mail.qp.gov.bc.ca>
Date: 1996/12/17
Message-ID: <32b5e37f.11367876@nntp.gov.bc.ca>#1/1

On Mon, 16 Dec 1996 11:25:58 +0100, Zoaib Saifuddin <Zoaib.Saifuddin_at_ubs.com> wrote:

>HI ALL,
>Can anyone pl. explain as to what's data warehousing all about??
>A detail description, if possible, please.
>
>Thanks in advance.
>CHEERS!
> - Zoaib.

Data Warehouses support a handfull of users doing massive queries.

OLTP systems support hundreds of users doing light weight transactions.

A Data Warehouse tends to be a large data base that complex data analysis queries are run against. For example it might contain all of an enterprises sales records for the last 5 years. Using this Financial Analysis (Bean Counters) can develope queries to discover trends or anomolies in the data. I have heard that in some cases one query has paid for a multi million dollar Data Warehouse.

Often the queries involve full table scans since the queries are always evolving and the DBA can only guess how best to index the data. Due to this a query can take a very long time to run and would not be suitable to run on a mission critical OLTP system. So what is done is upload the OLTP data on a weekly or monthly basis into the Data Warehouse. This can then be analysised without effecting day to day operations. Received on Tue Dec 17 1996 - 00:00:00 CST