On 31.08.2011 18:09, Jeff Davis wrote:
On Wed, 2011-08-31 at 09:20 +0300, Heikki Linnakangas wrote:
On 31.08.2011 09:14, Jeff Davis wrote:
First, a range is really a set. So if we take '[1,10)'::int4range and
cast that to numrange, we end up moving from a set of exactly 9 elements
to a set of an infinite number of elements. Going the other way is
probably worse.
...
Can you only provide casts that make sense, like between int4 and
numeric range types, and leave out the ones that don't?
There are certainly some casts that make sense, like
int4range->int8range. Do you think int4range->numrange also makes sense?
Not sure. It depends on whether you think of '[1,8]'::int4range as a
finite set of the integers between 1 and 8, or as a continuous range
from 1 to 8. I don't see harm in providing explicit casts like that, but
I would be very conservative with implicit and assignment casts.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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