Re: Idempotence and "Replication Insensitivity" are equivalent ?
Date: 22 Sep 2006 09:41:42 -0700
Message-ID: <1158943301.858418.110200_at_i42g2000cwa.googlegroups.com>
Jan Hidders ha scritto:
> Us? There's more than one of you? :-)
Plurale majestatis, like the Pope :)
>
> > Let's assume a Datetime field and this aggregate function:
> >
> > Central date = minDate + Half length of total time interval
> >
> > what would (E, S, A) be?
>
> You'd split that into computing (minDate, maxDate) and then do some
> post-processing. For (minDate, maxDate) you get:
> - E = (null, null)
> - S(d) = (d,d)
> - A((d1, d2), (d3, d4)) = (MIN(d1, d3), MAX(d2, d4))
> with MIN and MAX defined such that MIN(d, null) = MIN(null, d) = MAX(d,
> null) = MAX(null, d) = d.
I see. Interesting.
... but in case of a Median date, how would you proceed? Would it be all "postprocessing" ?
-P
>
> -- Jan Hidders
Received on Fri Sep 22 2006 - 18:41:42 CEST