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What you need is a fixed point decimal. I found this article asking the same question. http://stackoverflow.com/questions/1019939/ruby-on-rails-best-method-of-h

by vshlos 16y ago

What you need is a fixed point decimal. I found this article asking the same question. http://stackoverflow.com/questions/1019939/ruby-on-rails-best-method-of-handling-currency-money http://stackoverflow.com/questions/1019939/ruby-on-rails-bes... Fixed point is what is supposed to be used for money. Databases currently have a "Money" type.

malux85 16y ago
Yep this is the right way to go .. use the Money type when you can. Just remember though, don't hard code 2 decimal places through your system. I have had to write financial software that's needed to be flexible enough to be accurate to 4 decimal places. Some clients can have strict requirements on financial software, make sure you ask all the right questions first: - Do you have dollar discounts, or percentage discounts, or both? - When you calculate tax, you should do it on a per-line basis (don't sum up the invoice and calculate tax on the end - some countries / states / whatever can have tax exempt items) - When you calculate discount, calculate dollar value to N decimal places, then round to Y decimal places, then calculate tax on the rounded figure All of this might seem like a nightmare for a few cents, but it really matters if you're dealing with many items (where small differences add up over many items) or you have to integrate with another third party system, and you might need to make sure your totals match theirs exactly (to the cent) EDIT: Citing my sources ... I have worked on financial software that spans New Zealand, Australia and Global stuff too. I have had to integrate with (and learn intimately) 40+ accounting packages. All of them behave slightly differently in terms of rounding, but your best best is to - - Match the system you're integrating with - If you must 'lose' a cent, favour the customer (as the above comment says) Godspeed :)

by vshlos 16y ago

malux85 16y ago

Yep this is the right way to go .. use the Money type when you can. Just remember though, don't hard code 2 decimal places through your system. I have had to write financial software that's needed to be flexible enough to be accurate to 4 decimal places. Some clients can have strict requirements on financial software, make sure you ask all the right questions first: - Do you have dollar discounts, or percentage discounts, or both? - When you calculate tax, you should do it on a per-line basis (don't sum up the invoice and calculate tax on the end - some countries / states / whatever can have tax exempt items) - When you calculate discount, calculate dollar value to N decimal places, then round to Y decimal places, then calculate tax on the rounded figure All of this might seem like a nightmare for a few cents, but it really matters if you're dealing with many items (where small differences add up over many items) or you have to integrate with another third party system, and you might need to make sure your totals match theirs exactly (to the cent) EDIT: Citing my sources ... I have worked on financial software that spans New Zealand, Australia and Global stuff too. I have had to integrate with (and learn intimately) 40+ accounting packages. All of them behave slightly differently in terms of rounding, but your best best is to - - Match the system you're integrating with - If you must 'lose' a cent, favour the customer (as the above comment says) Godspeed :)