Thread: Create a function that updates the record with and timestamps

I would like to have postgres update the last_modified column with the current_date on an update of the record.
 
I am not sure if there is a very simple way of doing this?
 
Or, do I need to create a function and a trigger to call the row and update with new data and set the last_modified to current_date?
 
Here is the table.
 
CREATE TABLE price.price_table (
  PRICE_DATE DATE, 
  ID VARCHAR(13),
  OPENING NUMERIC(18,6),
  CLOSING NUMERIC(18,6),
  HIGHEST NUMERIC(18,6),
  LOWEST NUMERIC(18,6),
  VOLUME BIGINT,
  LAST_MODIFIED TIMESTAMP(6) WITHOUT TIME ZONE DEFAULT current_date,
CONSTRAINT PK_PRICE PRIMARY KEY (PRICE_DATE,ID));
 
Any help would be appreciated.
 
Cheers,
 
Chris
 

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In response to Chris Barnes :
> I would like to have postgres update the last_modified column with the
> current_date on an update of the record.
>
> I am not sure if there is a very simple way of doing this?
>
> Or, do I need to create a function and a trigger to call the row and update
> with new data and set the last_modified to current_date?

Yes, that's the way, a TRIGGER on UPDATE for each row. I think, the doc
contains an example.


Andreas
--
Andreas Kretschmer
Kontakt:  Heynitz: 035242/47150,   D1: 0160/7141639 (mehr: -> Header)
GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431  2EB0 389D 1DC2 3172 0C99

 
 
I see examples for updating tables using a function, but I would like to pull the row requested and modify the last_modified column with current_date and push the modified data back into the same row.
 
I did see an example of how to use old and new at this at this link, but it is vague.
 
http://www.faqs.org/docs/ppbook/x20655.htm#TRIGGERFUNCTIONVARIABLES

 
 

---

From: compuguruchrisbarnes@hotmail.com
To: pgsql-general@postgresql.org
Subject: [GENERAL] Create a function that updates the record with and timestamps
Date: Mon, 22 Mar 2010 12:58:49 -0400

.ExternalClass .ecxhmmessage P {padding:0px;} .ExternalClass body.ecxhmmessage {font-size:10pt;font-family:Verdana;} I would like to have postgres update the last_modified column with the current_date on an update of the record.
 
I am not sure if there is a very simple way of doing this?
 
Or, do I need to create a function and a trigger to call the row and update with new data and set the last_modified to current_date?
 
Here is the table.
 
CREATE TABLE price.price_table (
  PRICE_DATE DATE, 
  ID VARCHAR(13),
  OPENING NUMERIC(18,6),
  CLOSING NUMERIC(18,6),
  HIGHEST NUMERIC(18,6),
  LOWEST NUMERIC(18,6),
  VOLUME BIGINT,
  LAST_MODIFIED TIMESTAMP(6) WITHOUT TIME ZONE DEFAULT current_date,
CONSTRAINT PK_PRICE PRIMARY KEY (PRICE_DATE,ID));
 
Any help would be appreciated.
 
Cheers,
 
Chris
 
> Date: Mon, 22 Mar 2010 18:14:00 +0100
> From: andreas.kretschmer@schollglas.com
> To: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Create a function that updates the record with and timestamps
>
> In response to Chris Barnes :
> > I would like to have postgres update the last_modified column with the
> > current_date on an update of the record.
> >
> > I am not sure if there is a very simple way of doing this?
> >
> > Or, do I need to create a function and a trigger to call the row and update
> > with new data and set the last_modified to current_date?
>
> Yes, that's the way, a TRIGGER on UPDATE for each row. I think, the doc
> contains an example.
>
>
> Andreas
> --
> Andreas Kretschmer
> Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
> GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431 2EB0 389D 1DC2 3172 0C99
>
> --
> Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-general

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On Monday 22 March 2010 10:55:36 am Chris Barnes wrote:
> I see examples for updating tables using a function, but I would like to
> pull the row requested and modify the last_modified column with
> current_date and push the modified data back into the same row.
>
>
>
> I did see an example of how to use old and new at this at this link, but it
> is vague.
>
>
>
> http://www.faqs.org/docs/ppbook/x20655.htm#TRIGGERFUNCTIONVARIABLES
>


Something like this:

CREATE OR REPLACE FUNCTION public.ts_update()
  RETURNS trigger AS

$Body$
BEGIN
NEW.ts_update:=timeofday();
RETURN NEW;
END;
$Body$
  LANGUAGE 'plpgsql';


--
Adrian Klaver
adrian.klaver@gmail.com

In response to Richard Sickler :
>     > I am not sure if there is a very simple way of doing this?
>     >
>     > Or, do I need to create a function and a trigger to call the row and
>     update
>     > with new data and set the last_modified to current_date?
>
>     Yes, that's the way, a TRIGGER on UPDATE for each row. I think, the doc
>     contains an example.
>
>
>     Andreas
>
>
> From a novice: I use    last_updated_at timestamp without time zone NOT NULL
> DEFAULT now()

This works only for INSERT, but not for UPDATE.

test=# create table richard (id int, last_updated_at timestamp without time zone NOT NULL DEFAULT NOW());
CREATE TABLE
test=# insert into richard (id) values (1);
INSERT 0 1
test=# select * from richard ;
 id |      last_updated_at
----+----------------------------
  1 | 2010-03-23 06:54:28.656668
(1 row)

test=# select now();
              now
-------------------------------
 2010-03-23 06:54:42.443224+01
(1 row)

test=# UPDATE richard set id=2 where id=1;
UPDATE 1
test=# select * from richard ;
 id |      last_updated_at
----+----------------------------
  2 | 2010-03-23 06:54:28.656668
(1 row)


As you can see, the last_updated_at isn't up-to-date ;-)


Regards, Andreas
--
Andreas Kretschmer
Kontakt:  Heynitz: 035242/47150,   D1: 0160/7141639 (mehr: -> Header)
GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431  2EB0 389D 1DC2 3172 0C99