Re: example of insert timestamp - Mailing list pgsql-admin

From Aaron Bono
Subject Re: example of insert timestamp
Date
Msg-id bf05e51c0802251841i479790c0xf713282a961fd460@mail.gmail.com
Whole thread Raw
In response to Re: example of insert timestamp  (Jamie A Lawrence <postgres@jal.org>)
List pgsql-admin
On Mon, Feb 25, 2008 at 8:05 PM, Jamie A Lawrence <postgres@jal.org> wrote:

On Feb 25, 2008, at 8:19 PM, Gregory Williamson wrote:
>
> Perhaps, make the column so it has a default value of now, land then
> insert without specifying the timestamp column so it gets the
> default value:
>
> create table foo (q_i_time timestamp with time zone not null default
> now(), someval int);
>

This is what I do. For many tables, I also add a mod_time column with
an ON UPDATE trigger similar to the one previously posted. Even when
not needed for the table itself, in development, it can be very handy
to compare dodgy inserts/updates with commit logs when bug hunting...



I know you asked for something more like a create timestamp, but if you also want a modify timestamp, that would definitely need a trigger:

CREATE OR REPLACE FUNCTION "public"."modify_date_stamp_fn" () RETURNS SETOF opaque AS
'
BEGIN
    -- if a trigger insert or update operation occurs
    IF TG_OP = ''INSERT'' OR TG_OP = ''UPDATE'' THEN
        -- assigns the current timestamp
        -- into the modify date and time column
        NEW.modify_dt := now();
       
        -- displays the new row on an insert/update
        RETURN NEW;
    END IF;
END;
'
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;

CREATE TRIGGER "mytable_modify_dt_tr" BEFORE UPDATE
    ON "public"."mytable" FOR EACH ROW
    EXECUTE PROCEDURE "public"."modify_date_stamp_fn"();

This function is very generic and can be used for any and all of your tables so you don't have to create a function for each table as long as the column name is the same.

-Aaron

--
==================================================================
  Aaron Bono
  Aranya Software Technologies, Inc.
  http://www.aranya.com
  http://codeelixir.com
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