I thought the proper way to implement something like this was: - fixed point instead of floating point numbers for currency. - have a journal with transaction

I thought the proper way to implement something like this was: - fixed point instead of floating point numbers for currency. - have a journal with transactions such as withdrawals and deposits, plus a "checkpoint" at one point in time where you store the computed balance. e.g.: your balance is = starting balance for today + today withdrawals + today deposits