public void updateNString(String columnName, String nString) throws SQLException {
        throw new SQLFeatureNotSupportedException(resBundle.handleGetObject("jdbcrowsetimpl.featnotsupp").toString());
    }
This method is used for updating columns that support National Character sets.
It can be used for updating NCHAR,NVARCHAR and LONGNVARCHAR columns.
@param columnName name of the Column
@param nString the value for the column to be updated
@throws SQLException if a database access error occurs
@since 6.0
src/main/java/org/replicadb/rowset/sun/rowset/JdbcRowSetImpl.java