Martijn van Oosterhout <kleptog@svana.org> writes:
> We're talking here about a database with indexes to speed up
> intersection tests for arbitrary polygons, extensions to handle
> encryption, full text indexing and even builtin XML support.
... none of which require any extensions to the core type system.
AFAICS this could easily be implemented as a user-defined type, along
the lines of
CREATE TYPE measurement AS (value double, units text);
and if you want to constrain a particular column to contain only one
value of units, use CHECK.
The argument that we should extend the type system for this would become
a lot more credible if there were a widely-used extension in existence
for it to prove that there's sufficient demand.
regards, tom lane