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* Defaulting a column to 'now'
@ 2005-12-14 18:10 Ken Winter <ken@sunward.org>
0 siblings, 3 replies; 5+ messages in thread
From: Ken Winter @ 2005-12-14 18:10 UTC (permalink / raw)
To: pgsql-sql
How can a column's default be set to 'now', meaning 'now' as of when each
row is inserted?
For example, here's a snip of DDL:
create table personal_data (.
effective_date_and_time TIMESTAMP WITH TIME ZONE not null default 'now',.
The problem is, when PostgreSQL processes this DDL, it interprets the 'now'
as the timestamp when the table is created, so that the tables definition
reads as if the DDL were:
effective_date_and_time TIMESTAMP WITH TIME ZONE not null default '
2005-12-14 11:00:16.749616-06 ',
so all of the newly inserted rows get assigned effective_date_and_time = '
2005-12-14 11:00:16.749616-06 ', which in addition to being wrong leads to
uniqueness constraint violations.
~ TIA
~ Ken
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: Defaulting a column to 'now'
@ 2005-12-14 18:15 Bricklen Anderson <banderson@presinet.com>
parent: Ken Winter <ken@sunward.org>
2 siblings, 0 replies; 5+ messages in thread
From: Bricklen Anderson @ 2005-12-14 18:15 UTC (permalink / raw)
To: Ken Winter <ken@sunward.org>; +Cc: pgsql-sql
Ken Winter wrote:
> How can a column’s default be set to ‘now’, meaning ‘now’ as of when
> each row is inserted?
>
>
>
> For example, here’s a snip of DDL:
>
>
>
> create table personal_data (…
>
> effective_date_and_time TIMESTAMP WITH TIME ZONE not null default 'now',…
>
try with now(), instead of now
...
effective_date_and_time TIMESTAMPTZ not null default now()...
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: Defaulting a column to 'now'
@ 2005-12-14 18:15 Tom Lane <tgl@sss.pgh.pa.us>
parent: Ken Winter <ken@sunward.org>
2 siblings, 1 reply; 5+ messages in thread
From: Tom Lane @ 2005-12-14 18:15 UTC (permalink / raw)
To: Ken Winter <ken@sunward.org>; +Cc: pgsql-sql
"Ken Winter" <ken@sunward.org> writes:
> How can a column's default be set to 'now', meaning 'now' as of when each
> row is inserted?
You need a function, not a literal constant. The SQL-spec way is
CURRENT_TIMESTAMP
(which is a function, despite the spec's weird idea that it should be
spelled without parentheses); the traditional Postgres way is
now()
Either way only sets an insertion default, though. If you want to
enforce a correct value on insertion, or change the value when the
row is UPDATEd, you need to use a trigger.
regards, tom lane
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: Defaulting a column to 'now'
@ 2005-12-14 18:22 Keith Worthington <keithw@narrowpathinc.com>
parent: Ken Winter <ken@sunward.org>
2 siblings, 0 replies; 5+ messages in thread
From: Keith Worthington @ 2005-12-14 18:22 UTC (permalink / raw)
To: Ken Winter <ken@sunward.org>; +Cc: pgsql-sql
On Wed, 14 Dec 2005 13:10:50 -0500, Ken Winter wrote
> How can a column's default be set to 'now', meaning 'now' as of when each
> row is inserted?
>
> For example, here's a snip of DDL:
>
> create table personal_data (.
>
> effective_date_and_time TIMESTAMP WITH TIME ZONE not null default
> 'now',.
>
> The problem is, when PostgreSQL processes this DDL, it interprets the 'now'
> as the timestamp when the table is created, so that the tables definition
> reads as if the DDL were:
>
> effective_date_and_time TIMESTAMP WITH TIME ZONE not null default '
> 2005-12-14 11:00:16.749616-06 ',
>
> so all of the newly inserted rows get assigned effective_date_and_time
> = '
> 2005-12-14 11:00:16.749616-06 ', which in addition to being wrong
> leads to uniqueness constraint violations.
>
> ~ TIA
>
> ~ Ken
Ken,
effective_date_and_time TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT
('now'::text)::timestamp(6) with time zone
Kind Regards,
Keith
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: Defaulting a column to 'now'
@ 2005-12-15 17:20 Ken Winter <ken@sunward.org>
parent: Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 5+ messages in thread
From: Ken Winter @ 2005-12-15 17:20 UTC (permalink / raw)
To: 'Tom Lane' <tgl@sss.pgh.pa.us>; +Cc: pgsql-sql
Thanks, Tom (also Keith Worthington and Bricklen Anderson). That works.
~ Ken
> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> Sent: Wednesday, December 14, 2005 1:15 PM
> To: Ken Winter
> Cc: PostgreSQL pg-sql list
> Subject: Re: [SQL] Defaulting a column to 'now'
>
> "Ken Winter" <ken@sunward.org> writes:
> > How can a column's default be set to 'now', meaning 'now' as of when
> each
> > row is inserted?
>
> You need a function, not a literal constant. The SQL-spec way is
> CURRENT_TIMESTAMP
> (which is a function, despite the spec's weird idea that it should be
> spelled without parentheses); the traditional Postgres way is
> now()
>
> Either way only sets an insertion default, though. If you want to
> enforce a correct value on insertion, or change the value when the
> row is UPDATEd, you need to use a trigger.
>
> regards, tom lane
^ permalink raw reply [nested|flat] 5+ messages in thread
end of thread, other threads:[~2005-12-15 17:20 UTC | newest]
Thread overview: 5+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2005-12-14 18:10 Defaulting a column to 'now' Ken Winter <ken@sunward.org>
2005-12-14 18:15 ` Bricklen Anderson <banderson@presinet.com>
2005-12-14 18:15 ` Tom Lane <tgl@sss.pgh.pa.us>
2005-12-15 17:20 ` Ken Winter <ken@sunward.org>
2005-12-14 18:22 ` Keith Worthington <keithw@narrowpathinc.com>
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