What is Data Staging in SAP BW Technical

What is Data Staging in SAP BW Technical?
Many candidates who have completed the BW certification course are
appearing for interviews in SAP, Genovate, IBM and other
organizations. One of the popular technical interview questions for
the Business Warehouse BW interviews is relating to data staging.

Q). What is data Staging in SAP BW?
Answer: Data staging refers to the process of cleansing, manipulating and homogenizing data. In SAP BW, a staging engine is used for cleansing, manipulating and homogenizing data within the Infosource. It is very important to understand the difference in the way SAP handles master data and transaction data. Another important concept in data staging is PSA. PSA refers to Persistent Storing Area. PSA is a transperent table which is used to hold raw master and transactional data in BW. PSA however is not used in the transfer of master data in SAP.

The reason why PSA is an important component of the data staging
process is beacuse PSA holds data received from the BW server in the
original format without performing any transformations on the data