What is a Data Warehouse?
A data warehouse is a powerful database model that significantly enhances the user's ability to quickly
analyze large, multidimensional data sets. It cleanses and organizes data to allow users to make
business decisions based on facts. Hence, the data in the data warehouse must have strong analytical
characteristics.
Creating data to be analytical requires that it be: i. subject-oriented, ii. integrated, iii. time referenced, iv. non-volatile.
Subject-Oriented Data: In a data warehouse environment, information used for analysis is organized around subjects:
employees, accounts, sales, products, and so on. This subject specific design helps in reducing
the query response
time by searching through very few records to get an answer to the user's question.
Integrated : Data
Integrated data refers to de-duplicating information and merging it from many sources into one
consistent location. When short listing your top 20 customers, you must know that “HAL” and
“Hindustan Aeronautics Limited” are one and the same. Much of the transformation and loading
work that goes into the data warehouse is centered on integrating data and standardizing it.
Time-Referenced Data : Time-referenced data essentially refers to its time-valued characteristic. For example, the user
may ask “What were the total sales of product ,A for the past three years on New Year's Day
across region Y, Time-referenced data when analyzed can also help in spotting the hidden trends between
different associative data elements, which may not be obvious to the naked eye. This exploration
activity is
termed “data mining”.
Non-Volatile Data
The non-volatility of data, characteristic of data warehouse, enables users to dig deep into history
and arrive at specific business decisions based on facts.
Why Data Warehouse
The Data Access Crisis : If there is a single key to survival in the 1990s and beyond, it is being able to analyze, plan, and
react to changing business conditions in a much more rapid fashion. In order to do this, top managers, analysts, and knowledge workers in our enterprises, need more and better
information. Every day, organizations large and small, create billions of bytes of data about all
aspects of their business; millions of individual facts about their customers, products, operations
and people.
Data Warehousing: Data warehousing is a field that has grown from the integration of a number of different
technologies and experiences over the past two decades. These experiences have allowed the IT
industry to identify the
key problems that need to be solved.
