Data Warehouse is a relational database management system (RDBMS)
construct to meet the requirement of transaction processing systems. It can
be loosely described as any centralized data repository which can be queried
for business benefits. It is a database that stores information oriented to
satisfy decision-making requests. It is a group of decision support
technologies, targets to enabling the knowledge worker (executive,
manager, and analyst) to make superior and higher decisions. So, Data
Warehousing support architectures and tool for business executives to
systematically organize, understand and use their information to make
strategic decisions.
Data Warehouse environment contains an extraction, transportation, and
loading (ETL) solution, an online analytical processing (OLAP) engine,
customer analysis tools, and other applications that handle the process of
gathering information and delivering it to business users.
What is a Data Warehouse?
A Data Warehouse (DW) is a relational database that is designed for query
and analysis rather than transaction processing. It includes historical data
derived from transaction data from single and multiple sources.
A Data Warehouse provides integrated, enterprise-wide, historical data and
focuses on providing support for decision-makers for data modeling and
analysis.
A Data Warehouse is a group of data specific to the entire organization, not
only to a particular group of users.
It is not used for daily operations and transaction processing but used for
making decisions.
A Data Warehouse can be viewed as a data system with the following
attributes:
o It is a database designed for investigative tasks, using data from
various applications.
o It supports a relatively small number of clients with relatively long
interactions.
, o It includes current and historical data to provide a historical
perspective of information.
o Its usage is read-intensive.
o It contains a few large tables.
"Data Warehouse is a subject-oriented, integrated, and time-variant store of
information in support of management's decisions."
Goals of Data Warehousing
o To help reporting as well as analysis
o Maintain the organization's historical information
o Be the foundation for decision making.
Need for Data Warehouse
Data Warehouse is needed for the following reasons:
1. 1) Business User: Business users require a data warehouse to view
summarized data from the past. Since these people are non-technical,
the data may be presented to them in an elementary form.