On Fri, Apr 2, 2010 at 2:06 PM, Chris Travers <ch...@metatrontech.com> wrote: > Hi all; > > I have been having some discussion on the PostgreSQL lists about > spinning some of this off to a Pg-foundry project. However, one of > the big issues which is difficult in 1.3 and needs to be solved for > 2.0 is the issue of multi-currency balances. I would like to create a > multi-currency data type for PostgreSQL which can be currency aware > and address certain things we can't address today in terms of currency > conversions. > > The base type would look something like this: > > CREATE DOMAIN curr varchar(3); > CREATE TYPE monetary AS (amount numeric, denomination numeric, currency curr); > CREATE FUNCTION numeric(monetary) returns numeric as $$ select > $1.amount * $1.denomination; $$ language sql; > CREATE CAST (monetary AS numeric) with function numeric(monetary); > > An exchange rate conversion function would also be supplied though > perhaps not through this Pg-foundry module. Syntax would look > something like: > > SELECT convert_currency(monetary(1, 1, 'USD'), 'CAD', now()::date); > > I would also like to see payments handled differently, so that one > could mark the payment as converted at a specific point in time. The > further approach would be to allow us to properly track floating > balances in foreign currencies. There are two major use cases here: >
Awesome ideas. I have thought of taking this a step further and instead of having a base currency in a particular coin, a multi-currency system could have a high precision "base value unit". It's much like having a base coin, but in generic value units that have constant value. That is, your base VU will not fluctuate due to exchange rates and such. I know this dwelves into some complex economic theory but since you are evaluating ideas for multi-currency there is my .02. Best, Alejandro Imass [...] ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Ledger-smb-devel mailing list Ledger-smb-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ledger-smb-devel
