On 30 January 2011 02:55, Thom Brown <thom(at)linux(dot)com> wrote:
> On 29 January 2011 19:53, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
>> On Sat, 2011-01-29 at 14:42 -0500, Tom Lane wrote:
>>> Jeff Davis <pgsql(at)j-davis(dot)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.
>> I couldn't find another way to make a function with a definition like:
>> range(ANYELEMENT, ANYELEMENT) returns ANYRANGE
>> work. And it seemed worse to live without a constructor like that.
>> Also, it's not based on the btree opfamily right now. It's just based on
>> a user-supplied compare function. I think I could change it to store the
>> opfamily instead, if you think that's a better idea.
> Probably ignorance here, but why does the following not work?
> postgres=# select '[18,20]'::numrange @> 19;
> ERROR: operator does not exist: numrange @> integer
> LINE 1: select '[18,20]'::numrange @> 19;
> HINT: No operator matches the given name and argument type(s). You
> might need to add explicit type casts.
> I can see both the wiki page on range types and the pg_operator table
> appear to indicate this should work:
> postgres=# select o.oprname, tl.typname as lefttype, tr.typname as
> righttype from pg_operator o left join pg_type tl on o.oprleft =
> tl.oid left join pg_type tr on o.oprright = tr.oid where 'anyrange' in
> (tl.typname, tr.typname) and oprname = '@>';
> oprname | lefttype | righttype
> @> | anyrange | anynonarray
> @> | anyrange | anyrange
> (2 rows)
As for docs, anyrange will need mentioning as part of the information
about polymorphic types:
And on the pseudo-types page:
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