Re: Hi! I need basic info. on OLAP

Hi,

When you design an application your aim should be not to store/keep 'data' that can be derived/calculated from other/existing data. For example, monthly sales can be calculated from daily sales data(Invoices maybe). So you don't need to create a table to hold monthly data.
If you do you may have some drawbacks. For instance you may update/correct detail data, as a result of this you need to update aggregated data (monthly sales). Applications that used to process (create/maintain) data are named as OLTP appl..

By time, you accumulate tons of data, for ex. 10 years of Sales Data. In this case, to calculate monthly/yearly/.... data will be not efficient. It will take some/some time to derive aggregate reports which will be an obvious frustration to the end user.

So what you do? You create intermediate data holders like monthly sales data table, yearly sales data table. Usually you fill up those data holders (May be tables, may be files whatever) by batch processing. This approach is basically used for OLAP Appl.(Data Warehousing.. etc.)

This may be a simple rule?
Lowest granularity of data processing OLTP: Create/Update/Maintain Data. Anything above this OLAP: Analyze, Report, Evaluate Data Produce Warnings/Indicators

Hakan

Voit wrote:

> Check out http://www.whatis.com/
>
> Mark.
>
> "larry T." schrieb:
>
> > I interviewed with Oracle and just need basic info. on OLAP-- what is it and
> > what does it do?
Received on Sat Mar 27 1999 - 01:10:19 CST