updateFinanceExchangeRate

Mutation

Corrects a stored rate's value or the day it applies from. There is no delete and no archive: a rate is superseded by a later dated row, and a row entered against the wrong day is moved to the right one. Editing marks the rate manual, so a later provider refresh cannot revert a correction someone made on purpose. Access: 'setupUpdate' in a workspace where finance is enabled. Errors: the rate does not exist; the new rate is not a decimal greater than zero; the new date already holds a rate for this pair.

Returns FinanceExchangeRate !.