Hi Venkat,
Seems like your data source and cube are standard one. you can get the useful information from the table RSOSFIELDMAP
If your data flow is Data source --> info cube.
SE11 - RSOSFIELDMAP, go to contents, give the data source name, you will see ecc field name and respective bw objects name.
ECC field name holds - FIELDNAM
BW object name holds by - IOBJNM.
Thanks