The bulk of the organization’s raw data saves at multiple operational systems, logs, and unstructured data sources. A data warehouse (DW) is a centralized location that brings all of that data together and optimizes it for reporting and analysis. Data warehousing is a well-defined and structured application of BI.
Extract, transform, and load (ETL) processes are created that copy, clean, and load data from source systems into the data warehouse. A data warehouse implementation often focuses on business processes that generate data. That data is then turned into Key Performance Indicators (KPIs) and other valuable metrics. Once in the DW this data can be easily consumed by many other applications and tools all with consistent results.
The benefits of Data Warehouses are:

• Standardizes data across an organization
• Quick and easy access to data
• Data quality and consistency
• Smarter decisions for companies – moves towards fact-based decisions.
• Reduces costs- drops products that are not doing well
• Increases revenue – works on high selling products.
• Better enterprise intelligence.