Re: setting default value by "trigger" - Mailing list pgsql-general

From Barbara Lindsey
Subject Re: setting default value by "trigger"
Date
Msg-id 4027C07C.7000607@cog.ufl.edu
Whole thread Raw
In response to setting default value by "trigger"  (Barbara Lindsey <blindsey@cog.ufl.edu>)
List pgsql-general
This sure looks a lot like what I already tried, but I will try it again...

d L. wrote:
> This works on 7.3.4:
>
> CREATE TABLE foo (id SERIAL, starttime TIMESTAMP, endtime TIMESTAMP);
>
> CREATE FUNCTION adjust_end_time() RETURNS "trigger" AS '
> BEGIN
>         IF NEW.endtime ISNULL THEN
>             NEW.endtime := NEW.starttime;
>         END IF;
>         RETURN NEW;
> END;'
> LANGUAGE plpgsql;
>
> CREATE TRIGGER foo_trigger
>     BEFORE INSERT ON foo
>     FOR EACH ROW
>     EXECUTE PROCEDURE adjust_end_time ();
>
> INSERT INTO foo(starttime, endtime) VALUES (now(), now());
> INSERT INTO foo(starttime) VALUES (now());
>
> SELECT * FROM foo;
>
> On Monday February 9 2004 9:24, Barbara Lindsey wrote:
>
>>I have a case where I am collecting a "Start Date" and an "End Date".
>>I would like to default the "End Date" to the "Start Date" value if only
>>the "Start Date" is entered.
>>I tried setting this as default on the table, but it was not permitted.
>>So, now I am trying to figure out how to do it with a trigger or
>>trigger/function combination.
>>
>>I tried doing it with a rule using "INSTEAD" on INSERT, but that gave an
>>"endless recursion" error, which did make ssense after I looked at it
>>more closely.
>>
>>I also tried making a trigger, which called a function that changed the
>>value of the NEW.enddate to the NEW.startdate value if NEW.enddate is
>>NULL, but I got an error saying that the NEW. values were not available
>>yet (doing trigger BEFORE INSERT).
>>
>>Has anyone else done something like this, and if so, what approach
>>worked for you?
>>Thanks.
>>Barb
>



--
Barbara E. Lindsey,
COG RDC
Phone: (352) 392-5198 ext. 314     Fax: (352) 392-8162

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