Data Warehouses and Data Mining

Data Warehouse

Data warehouse was first coined by Bill Inmon in 1990. According to the Inmon, a data warehouse is a subject-oriented, integrated, time-variant, and non-volatile collection of data. This data helps analysts to make informed decisions in an organization.

  • A data warehouse is a database that is kept separate from the organization's operational database.
  • Possesses consolidated historical data, which helps the organization to analyze its business.
  • Help in the integration of diversity of application systems. Why a data warehouse is separated from operational databases?
  • An operational database is constructed for well-known tasks and workloads such as searching particular records. Indexing etc.
  • An operational database query allows reading and modifying operations.
  • An operational database maintains current data.


  • Data warehouse is subject oriented because it provides information around a subject.
  • Data is integrated from heterogeneous sources.
  • Data collected in a data warehouse is identified with a particular time period.
  • Data is non volatile.
  • A data warehouse does not require transaction processing, recovery, and concurrency controls.