Re: Range-Types in 9.2 - Mailing list pgsql-general

From Misa Simic
Subject Re: Range-Types in 9.2
Date
Msg-id CAH3i69k3e3i7ZROPHJer6_Los8QEDyPOp-dkqWDPVfYtedRPgw@mail.gmail.com
Whole thread Raw
In response to Re: Range-Types in 9.2  (Jeff Davis <pgsql@j-davis.com>)
List pgsql-general
Hi,

I just wonder about scenario in which time range would be usefull? (I mean, just time - not timestamp...)

We have some scenario where we use time range as settings... Concrete case is: for each hour employee worked between 20:00 and 08:00 should be paid x, between 08:00 - 20:00 y... ( stored in table as timestamp range with check constraint for lower to fixed date, just because of must not overlap constraint - though could be and 2 time columns...)

Now for actuall working period (timestamp range), we are building dynamic timestamp ranges, taking date from actual working period and time from settings, to calculate  hours what belongs to x, y rates...


Thanks,

Misa

On Monday, August 6, 2012, Jeff Davis wrote:
On Fri, 2012-08-03 at 10:42 -0700, Jeff Davis wrote:
> On Fri, 2012-08-03 at 17:06 +0200, Andreas Kretschmer wrote:
> > great feature, but i can't find a TIMERANGE, i want to store time-ranges, for
> > instance [10:00:00,16:00:00), how can i do that?
>
> CREATE TYPE timerange AS RANGE ( subtype = time );
>
> That's the simple answer. I believe we discussed including this as a
> built-in range type at some point, but decided against it. I can't
> remember the reason right now.

Time of day is a cycle (I forget who pointed this out), so a limit of
24:00:00 is fairly restrictive. It happens that daytime ranges like
[14:00,15:00) are more common; but it doesn't seem unreasonable to say
[22:00,02:00) either.

So, an interpretation where time of day has a total order is only useful
really for a daytime schedule (which is still useful, but perhaps not
general enough to include in core). We might be able to make it work as
ranges within a 24-hour cycle, but that will require more thought.

Regards,
        Jeff Davis


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