Hi Monissha,
- Are these data types are just being filled up in the UI and not used internally in case of a row table?? - It doesn't matter whether the table is row or column store table. Any table you create in HANA(through SQL or UI) will have column store data type for internal usage
- data types STRING & CS_STRING are totally different as STRING data type is not a defined data type under column store data type? - SQL data types are mapped to column store data types. Refer to the link shared by me in previous reply.
Regards,
Vivek