Hi Sandeep;
Here I would take a look at the SAP Student Lifecycle Management transactions of Student File (PIQST00 & PIQSTM) for maintaining student master data. For changing grades I suggest you use PIQST10 or PIQSTAW10. These services can either be delivered via the NWBC 4.0 client and/or the NWBC webclient.
br
Rob