Karel, Andreas,
> > My idea is special internal API that will usable for new datetypes
> > programming if type is defined as "numeric + symbol", for example things
> > like speed, weight, currency.. etc.
>
> A type consisting of value and unit probably makes pgsql even more first
> choice for technical applications. Please note that %, k, M and so on
> are scales, not units and thus dont belong into that type.
The difference with currency would be the lack of a fixed conversion for
different units. For example, you can:
10m == 1000cm
7l == 0.07m^3
But you can't reasonably:
10USD == 6.25UKL
... because that would require a query to money.yahoo.com to establish.
--
Josh Berkus
Aglio Database Solutions
San Francisco