I am trying to append to my Ledger credits showing in my downloaded Bank Statements. In my Ledger Table I have set 3 fields as Primary Keys (Donor Number, Amount and Date) as there should never be duplicate entries for all 3 fields. My append query selects the credits from my Bank Statement and inserts them into the Ledger. But I would expect the use of the 3 Primary Keys to ensure that only new credits are added to the Ledger. But I am finding that all credits (including entries already in the Ledger) are being appended. How can I get only new credits added to my Ledger?