there are previous alike threads Shyamala, just check once, the same datasource in question has been discussed.
For Step by step 0method you can check this below document though : http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/302d4b15-5847-2a10-93bb-9c45d9f06b16?overridelayout=t…
thanks!