Help with a one time only calculated field.
I need a field to calculate one time only once a reference field is picked. I read a similar question earlier, but it only calculated on record creation.
What I currently have:
I have a chassis table: F F3 C M (Ford E450, E350, Chevy, mercedes). Each one has an correspoinding cost.
When I select the chassis from a drop down list based on that table it will bring up price for that chassis, and then another field will calculate the "upfit" by subtracting the chassis cost from the total cost (which I input). that worlkds fine...here is the problem.
That chassis price will change as the years go on. I thought about putting model years in for the chassis each with its own price (F12, F13) but then that drop down list will get bigger and bigger...plus we may change the price twice in a year.
I want it to calculate the cost the first time, but when I change the chassis price, only put the new price in on new records, not go back and update the existing records. I really only need it to calculate the price once I select the chassis.
I thought about using a value list instead that only lists "current" chassis models. F12, F3-12, C12, M12 and then have an "IF" funtion that calculates a chassis cost off of that list. When the chassis price increases, change the chassis value list names and the prices in the IF function...that way none of the old ones get changed and I only see the NEW chassis options in the drop down list...but it seems inefficient. There has to be a cleaner way.