Hi Vignesh,
You can use the Data Loader found on the console page to update profiles and relationships in mass. I have never done relatioships but have frequently used the profile update. You can only run for one source at a time, meaning your input file (I generally use a .csv) must have only 1 source system in it, and all the crosswalks for that sourcesystem and the fields you want to update. In Data Loader you then map the fields to update, and set the crosswalk key to the source and where the crosswalk key is found in the table. A VERY IMPORTANT step is when ready to run the load Choose PARTIAL UPDATE, if you are not sending every attribute on the Crosswalk. by Default Reltio has Full Update. If you do not choose partial you will erase all the data in the attributes not included in your file. I would be happy to demo this for you. Search Data Loader in documentation. There are several sections on loading entities, loading relationships etc.
Thank you,
angie