Hi Rohith,
You cannot issue update commands via oData service, however you can use XSJS to post/update/delete records to HANA.
XSJS is a server side script that connects directly to the HANA server and can execute SQL statements such as SELECT/INSERT/UPDATE/DELETE. You can use a client side page which makes an ajax call passing certain parameters to the server side XSJS script, which can then insert/update/delete records to HANA.
You may refer to the following blog by Henrique Pinto which provides step by step details on how to insert values to HANA using an XSJS script.
http://scn.sap.com/docs/DOC-33902
Kind Regards,
Sharan