What is Datawarehouse?

A Data Warehouse is a repository of integrated information, available for queries and analysis.Data and information are extracted from heterogeneous sources.It is merely a collection of data marts representing historical data from various operations in the company.

Data mart :

Its a segment of data warehouse that can provide data for reporting and analysis on a section, unit, department, (e,g). sales,payroll,production.

Why Data warehousing?

Benefits:

• Datawarehouses are designed to perform aggregate queries running on large amounts of data .

• The structure of data warehouse is easier for end users to navigate and understand.
• Queries that would be complex in very normalized database could be easier to build and maintain in data warehouses decreasing their workload on transactions.
• Efficient way to manage demand for lots of information from lots of users.
• Efficient way to manage and report on data that is from a variety of sources, non uniform and scattered throughout a company.
• Provides the capability to analyze large amounts of historical data that can provide an organisation with competitive advantage

Components of Data Warehouse:

Data Warehouse system consists of three components namely,

• A database :Pulls the selective data from the existing operational databases such as Accounting, Forecasting, HumanResources, Marketing, Engineering & Sales
  
• A query tool : This tool enable the users to access to the real time Data Warehouse database for query generation, creating a report, analysing the reports and also for exporting the data to numerious formats
• Database interfaces : It allows for updating the database daily, weekly or on a monthly basis.In other words it acts as a simple bridge for transfer of data between operations database to the data warehouse