Context : I have a field in a form that fetches it's value in another field in another form based on the value entered in another field in the same form (like a lookup field). That bit is taken care of with a script that fetches the value "On success" so the value is added to the field when creating a new record or updating an existing record.

What I'm looking for now is a way to update in one step this field for all existing records at once. Thanks for you help!