Changing billing rate
I use a FM database to keep track of billing.
There is a rate field - the rate I charge each client per hour. This rate is multiplied by hours to come up with the bill total.
I didn't think of this when I built the DB a few years back - I now want to raise the rate for some clients.
If I change the hourly rate for a client, all past paid invoices change to reflect the new rate.
I have no idea how to approach this problem.