Data Warehouse

Definition : A single, complete and consistent store of data obtained from a variety of different sources made available to end users in a format that they can understand and use in a business context.
Why?
The users want :
Data should be integrated across the enterprise
Data reporting should be uniform irrespective of how it is stored
Data should be available when we want it
Summary data had a real value to the organization
Historical data holds the key to understanding data over time

Who are users? Users are primarily managers and business people who want to analyse the data to bring the changes to their process , hence increasing profits.

Goals of a Data warehouse:

1) It must make an organization’s information more accessible
2) It must make the organization’s information consistent
3) It must adapt itself to change
4) It must defend organization’s data
5) It must provide data for improved decision making

1) It must make an organization’s information more accessible:

This is one of the main goals of a datawarehouse. Any organisation can have multiple databases and systems for controlling and operating data. A Datawarehouse gets inputs from all these systems and creates a single source for data requirements.

2) It must make the organization’s information consistent

The datawarehouse should be able to provide a singe source of data ( of course a single version of truth )
3) It must adapt itself to change

A datawarehouse a\can increase in size. It should be able to scale itself.
4) It must defend organization’s data

The datawarehouse must be able to protect itself from unauithorized access. Also updates to datawarehouse should be subjected to access control.

5) It must provide data for improved decision making

Final result of the datawarehouse must be its capability of providing data for reports.