Input specific fields into DB table

My input csv file is of this format - customer_id(string), type 1, type 2
And my DB table person_table is of this format:
person id(int), person_index(int), customer_id(string), timestamp wherein the person_id is auto generated.

I used csv input and table output with 'specify DB fields'.

But I get this error: Error updating row. Field person_index doesnt have a default value.

Any ideas why?