On Sun, Jun 13, 2021 at 11:25:05AM -0400, Jonathan S. Katz wrote:
> On 6/13/21 10:57 AM, Zhihong Yu wrote:
> > +/* Turn multirange into a set of ranges */
> >
> > set of ranges: sequence of ranges
>
> I believe "set of ranges" is accurate here, as the comparable return is
> a "SETOF rangetype". Sequences are objects unto themselves.
>
I believe the point was that (in mathematics) a "set" is unordered, and a
sequence is ordered. Also, a "setof" tuples in postgres can contain
duplicates.
The docs say "The ranges are read out in storage order (ascending).", so I
think this is just a confusion between what "set" means in math vs in postgres.
In postgres, "sequence" usually refers to the object that generarates a
sequence:
| CREATE SEQUENCE creates a new sequence number generator.
--
Justin