# Modifying Data By Import
It is possible to modify existing data in Auctria by importing an Excel file that has the key field for the table mapped.
When you import bidders from an Excel file, if you have a bidder# column in your spreadsheet, and you map that column to the bidder# field, then the system will look for a matching bidder# for each row.
If there is a matching bidder in the system then this bidder will be modified with the information from the other mapped columns in the spreadsheet rather than inserting a new bidder.
If the bidder# is blank, or the bidder# does not exist in the system then a new bidder record will be created.
# Key Fields
The following tables list the key field for commonly imported tables
It is not possible to modify exisiting records when importing into the 'winning bid' or payments table.