Re: Content for talk on Postgres Type System at PostgresConf

On 2/29/24 1:38 PM, Guyren Howe wrote:
> In case I’m not correct on the issues with these types, myself, what
> are the misconceptions, or where might I find them for  myself?
>
> My current understanding:
>
> * character is fixed-length, blank-padded. Not sure when you’d want
> that, but it seems clear. Is the name just confusing?
> * timestamptz is just converted to a timestamp in UTC. Folks might
> imagine that it stores the time zone but it doesn’t.
>
The issue I see is people getting confused when it come back rotated to
whatever TimeZone is set to, which can change from client to client.
>
> * time with time zone *does* store the time zone, but this isn’t
> actually useful and should be avoided (I’m not entirely sure why
> and the docs only gesture at the problems without stating them, IIRC)
> * money is a fixed-point decimal value, the number of decimal places
> is locale determined. I’m not aware of any particular problems
> with that
>

test=# show lc_monetary ;
 lc_monetary
-------------
 en_US.UTF8
(1 row)

test=# select 1000::money;
   money
-----------
 $1,000.00
(1 row)

test=# set lc_monetary = 'en_GB.utf8';
SET
test=# select 1000::money;
   money
-----------
 £1,000.00

> On 29 Feb 2024 at 01:11 -0800, Laurenz Albe
> <laurenz(dot)albe(at)cybertec(dot)at>, wrote:
>> On Wed, 2024-02-28 at 17:08 -0800, Guyren Howe wrote:
>>> I am to talk about Postgres’s type system at PGConf:
>>>
>>> https://postgresconf.org/conferences/2024/program/proposals/postgres-s-type-system
>>>
>>> I picked the issue because I think it’s poorly understood, greatly
>>> under-discussed, and an excellent way to empower postgres users.
>>>
>>> What would you want to see in such a talk?
>>
>> It might be good to explain how "timestamp with time zone" works.
>> That's often confusing for beginners, because it is different from
>> other databases and arguably deviates from the SQL standard.
>>
>> Perhaps it would be good to warn people about using data types like
>> "character", "time with time zone" and "money".
>>
>> Yours,
>> Laurenz Albe

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com