SAP Business Warehouse (BW) is an enterprise datawarehousing tool. The data stored in all the Software systems in your organization over the years can be collected into one single Datawarehouse and then you can create reports over the data for reporting purpose.
SAP BW Integrates data from different sources transforms and consolidates the data, does data cleansing, and storing of data as well. It also includes data modelling, administration and staging area.