Jeff Davis <pgsql@j-davis.com> writes:
> On Fri, 2011-01-28 at 21:52 +0000, Thom Brown wrote:
> Also, if I try the same, but with a different name for the type, I get
> the same error. Why does that restriction exist? Can't you have
> types which happen to use the exact same subtype?
> At first, that's how I designed it. Then, I realized that the type
> system needs to know the range type from the element type in order for
> something like ANYRANGE to work.
That seems like a fairly bad restriction. In a datatype with multiple
useful sort orderings, it'd be desirable to be able to create a range
type for each such ordering, no? I'd be inclined to think of a range
type as being defined by element type plus a btree opfamily. Maybe it'd
be okay to insist on that combination as being unique.
regards, tom lane
