Thursday, July 31, 2008
What is a data Warehouse?
"A warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process".
subject-oriented : Data that gives information about a particular subject instead of about a company's ongoing operations.
integrated : Data that is gathered into the data warehouse from a variety of sources and merged into a coherent whole.
time-variant : All data in the data warehouse is identified with a particular time period.
non-volatile : Data is stable in a data warehouse. More data is added but data is never removed. This enables management to gain a consistent picture of the business.
What is Data WareHousing?
Data warehousing is essentially what you need to do in order to create a data warehouse, and what you do with it. It is the process of creating, populating, and then querying a data warehouse.
Data WareHousing tool
SAP-BW, SAP-BI (7.0, the latest version).
There area three data warehousing functions:
Modeling : This talks about, the architecture and design of the data objects, how you are going to store the data and where and what type of data.
Extraction: This is about how you are loading the data from OLTP (R/3) to OLAP (SAP-BW). In this process, you will take care of filtering the data and adding up more data based business requirements. Here you have various extractors using which you can extrat data of a particular application.
Reporting: What ever is done till now on a warehouse tool, is ultimtely to generate a report. Reporting is done based on business requirement, for the higher executives to take business decisions after analysing the reports.