importing field contents on a calculated field
I have a calculated field on my customers table. This field, Account_number is created when a customer places an order. It is linked to an accounts table that creates the account pk number and recieves the customer fk when a account record is created.
The account_number field in my customers table provides a unique account number that comprises the last 3 digits of the customer id number and the first three letters of the surname.
However, I am importing some old customer records which already have their account numbers calculated - but the account number on these imported records is calculated in a different way.
I have been able to import these records and into my new customers table by turning off the calculated field to just an edit field. But when I turn it back on to calculated, for new customers, it will alter all the other imported account number fields, How do I get around this.??