Re: T is a mandatory date time separator in RFC3339 but documentation states differently

It seems I was wrong.
Now T is mandatory in ISO8601 and from RFC3339 it seems this requirement is
relaxed.

-
https://stackoverflow.com/questions/9531524/in-an-iso-8601-date-is-the-t-character-mandatory#comment89287877_34006233
-
https://en.m.wikipedia.org/wiki/ISO_8601#Combined_date_and_time_representations
-
https://stackoverflow.com/questions/65000211/is-using-t-to-separate-date-and-time-inconsistent-with-rfc3339

On Mon, Nov 13, 2023 at 12:03 PM Roman Frołow <rofrol(at)gmail(dot)com> wrote:

> So what should be changed?
>
> postgresql docs say that it is consistent with rfc3339 using space.
>
> Also look at this:
>
> > In addition, an uppercase "T" character MUST be used to separate date
> and time
>
> https://validator.w3.org/feed/docs/error/InvalidRFC3339Date.html
>
> I would say that postgresql is not consistent with rfc3339, but rather
> with ISO8601 which is very flexible in regard to separator etc.
>
> On Mon, Nov 13, 2023 at 11:23 AM Erik Wienhold <ewie(at)ewie(dot)name> wrote:
>
>> On 2023-11-11 23:45 +0100, PG Doc comments form wrote:
>> > The following documentation comment has been logged on the website:
>> >
>> > Page: https://www.postgresql.org/docs/16/git.html
>> > Description:
>> >
>> > >ISO 8601 specifies the use of uppercase letter T to separate the date
>> and
>> > time. PostgreSQL accepts that format on input, but on output it uses a
>> space
>> > rather than T, as shown above. This is for readability and for
>> consistency
>> > with RFC 3339 as well as some other database systems.
>>
>> This note probably refers to section 5.6. of RFC 3339 [1] which allows
>> applications to choose space over "T".
>>
>> > https://www.postgresql.org/docs/current/datatype-datetime.html
>> >
>> > Short answer: T (or t as discouraged alternative).
>> >
>> > After reading on this as much as I could, it turns out the time
>> separator
>> > must be a T or t. What has made think this way is first of all this
>> thread
>> > in the GNU lists where F. Alexander Njemz contacted the authors of
>> RFC3339
>> > Graham Klyne and Chris Newman asking if T is mandatory and got this
>> response
>> > from Mr. Klyne:
>> >
>> > > In short: "yes"
>> > >
>> > > Per section 5.5, the intent in this draft was to specify a timestamp
>> > format using elements from and compatible with 8601, but eliminating as
>> far
>> > as reasonable any variations that could make timestamp data harder to
>> > process. This includes making the 'T' mandatory in date+time values.
>> >
>> > Just for clarity's sake, this is stated in the section 5.5:
>> >
>> > > Simplicity is achieved by making most fields and punctuation
>> mandatory.
>>
>> But the word "most" certainly leaves some wiggle room.
>>
>> > This clearly clashes with a non-mandatory T and strongly makes me think
>> that
>> > the this syntax in that problematic passage refers to ISO8601 and not
>> > RFC3339.
>> >
>> >
>> https://stackoverflow.com/questions/63783868/what-are-valid-date-time-separators-in-rfc3339-strings/63882162#63882162
>>
>> [1] https://datatracker.ietf.org/doc/html/rfc3339#section-5.6
>>
>> --
>> Erik
>>
>