What is Datawarehousing and what are the tools used in this? & which tool has the large scope. Kindly share your thoughts.

Datawarehousing is a combined process of ETL and BI. DataWarehouse is a Repository where consolidated, Integrated, historical and subject Oriented data is present to generate the analytical reports. Most popular DataWarehousing tools are ERWin and ERStudio.

Thanks

Datawarehouse is a database used as a cube to navigate through information using several dimensions. 

the microsoft tools such as Integration Services to extract, transform and load the information,  Analysis Services to create the cub and Reporting Services  for presentation data. Also  QlikView and Oracl  tools.