Re: Conditional rule?

Hm... I'm a true newbie when it comes to plpgsql and triggers, but I looked
through some texts and managed to come up with the following rather odd (to
me at least) behaviour:

*****

create table news (
id serial,
title varchar(50),
time timestamp
)

create table news_un (
news_id int
)

Table "news_un"
Attribute | Type | Modifier
-----------+---------+----------
news_id | integer |

create function setpublish() returns opaque as '
begin
insert into news_un select news_id_seq.last_value where new.time is not
null;
return null;
end;
'
language 'plpgsql';

create trigger newstrigger after insert on news for each row execute
procedure setpublish();

*****
Attempting to do an insert to news:

testruledb=# insert into news (title, time) values('Test', now());
INSERT 24028 1
testruledb=# select * from news; select * from news_un;
id | title | time
----+-------+------------------------
48 | Test | 2000-07-27 19:20:24+02
(1 row)

news_id
---------
47
48
(2 rows)

I also tried setting time to null:

testruledb=# insert into news (title) values('Test2');
INSERT 24031 1
testruledb=# select * from news; select * from news_un;
id | title | time
----+-------+------
50 | Test2 |
(1 row)

news_id
---------
49
(1 row)

There's obviously something about triggers and functions I don't understand,
any help would be greatly appreciated.

Thanks

André Næss

----- Original Message -----
> "=?iso-8859-1?B?QW5kcukgTuZzcw==?=" <andre(dot)nass(at)student(dot)uib(dot)no> writes:
> > I wish to make rule looking something like this:
> > create rule newsrule as
> > on insert to news do
> > if new.publishtime is not null insert into news_unpublished
> > values(new.id);
>
> > I.e. "On an insert to news, if new.publish is not null, insert the new
> > post's id into news_unpublished.
>
> What you want here is a trigger, not a rule. The closest you could come
> with a rule is to copy *all* unpublished ids into news_unpublished each
> time something got inserted into news. There are applications for that
> sort of thing, but this ain't it. See the trigger examples in the
> plpgsql or pltcl sections of the manual.
>
> regards, tom lane
>