On Fri, Apr 9, 2010 at 5:49 PM, Jeff Davis <pg...@j-davis.com> wrote: >> It may or may not be worth building the concept of a unit >> increment into the type interface machinery, though: one could imagine >> two different range types built over the same base type with different >> unit increments - e.g. one timestamp range with unit increment = 1s, >> and one with unit increment = 1m. Under the first type [4pm,5pm) = >> [4pm,4:59:59pm], while under the second [4pm,5pm) = [4pm,4:59pm]. > > Right. Part of the interface could be a unit() function, and that can > return whatever you want. > > I was originally thinking about it in terms of next() and prev(), but > you could build those from +, -, and unit().
The advantage of specifying a + and a - in the type interface is that the unit definition can then be specified as part of the type declaration itself. So you can do: CREATE TYPE ts_sec AS RANGE OVER timestamp (UNIT = '1s'); CREATE TYPE ts_min AS RANGE OVER timestamp (UNIT = '1m'); All of the stuff about defining + and - is hidden from the user - it's part of the type interface, which is pre-created. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
