how to use currency exchange with exchange_rate that is saved in ActiveRecords model?

[laptopmutia]

so I have a transaction model and in this Active Records model I have column that hold, currency buying_price and selling_price

I want to use the exchange rates using this two column, is that possible?

because from the docs money have a complicated exchange rates, it stores the exchange rates in a global/gem config instead per model

here is my schema

  create_table "bills", force: :cascade do |t|
    t.decimal "selling_currency_rate", default: "0.0", null: false
    t.decimal "buying_currency_rate", default: "0.0", null: false
    t.bigint "foreign_currency_id"
    t.decimal "total_amount"
  end

the default or local currency is always IDR

[sunny]

One way to get the current exchange rate could be to determine it on the spot. E.g.: 1.to_money("EUR") / 1.to_money("IDR").