If I learned one thing from designing is similar systems in the past is to avoid referential data as much as possible haha I did not go into such depth here, b

If I learned one thing from designing is similar systems in the past is to avoid referential data as much as possible haha I did not go into such depth here, but individual function calls record (duration, billing_rate, total_cost) as plain values and also references `billing_rate` used (setting foreign constraint to restrict to avoid accidentally nuking data). Had at least one instance where an engineer in our team modified a value in rates table causing havoc to the entire billing system that relied on referential values used to calculate balances I want to build in as much redundancy as possible, even if that means duplicating data in several places