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0 pointsskissane3y ago0 comments

> If we used a composite currency type, the currency_type field would be highly redundant.

It can help prevent the bug in which someone adds up multiple currencies without conversion.

“25 USD + 25 EUR” will either fail or work via some currency conversion routine.

“25 + 25” will produce a meaningless and useless wrong answer.

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1 comments · 1 top-level

Yes, this is exactly what I’ve done previously. For example, I implemented a sum() aggregate function that took “monetary” (currency + value) composite types and raised an exception if the currencies were not all the same.

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