What's Data Warehouse?
A data warehouse is a type of data management system that is designed to enable and support business intelligence (BI) activities, especially analytics. Data warehouses are solely intended to perform queries and analysis and often contain large amounts of historical data. The data within a data warehouse is usually derived from a wide range of sources such as application log files and transaction applications.
Why Data Warehouse is Important?
Data warehouses offer the overarching and unique benefit of allowing organizations to analyze large amounts of variant data and extract significant value from it, as well as to keep a historical record.
Four unique characteristics (described by computer scientist William Inmon, who is considered the father of the data warehouse) allow data warehouses to deliver this overarching benefit. According to this definition, data warehouses are
Subject-oriented. They can analyze data about a particular subject or functional area (such as sales).
Integrated. Data warehouses create consistency among different data types from disparate sources.
Nonvolatile. Once data is in a data warehouse, it’s stable and doesn’t change.
Time-variant. Data warehouse analysis looks at change over time.
A well-designed data warehouse will perform queries very quickly, deliver high data throughput, and provide enough flexibility for end users to “slice and dice” or reduce the volume of data for closer examination to meet a variety of demands—whether at a high level or at a very fine, detailed level. The data warehouse serves as the functional foundation for middleware BI environments that provide end users with reports, dashboards, and other interfaces.