Re: automatic update

A trigger is the right way.  Rules rewrite a statement whereas triggers are at
row level.

so in plpgsql:

create or replace function trig_param_ins_upd() returns trigger as '
begin
    new.ts = current_timestamp;
    return new;
end;' language 'plpgsql';

create trigger trig_param_ins_upd before insert or update on param
for each row execute procedure trig_param_ins_upd();

now whenever a new row is insert or a row is updated the trigger will ensure
that ts always contains the current timestamp.

Rgds,

Jason

On Tue, 2 Sep 2003 06:56 pm, Alessandro GARDICH wrote:
> Hi to all ...
>
> I'm looking to a way to auto update some fields of a row when other
> fileds are updated.
>
> the table structure are simple,
>
> CREATE TABLE param (
> id int4 PRIMARY KEY,
> val int4,
> ts timestam(3) DEFAULT CURRENT_TIMESTAMP
> );
>
> so when a new entry are insert ts areautomatically update,
> but i would make the same on update ...
>
> i would that on
> UDPATE param SET val=100 WHERE id=1;
>
> also ts field have to be updated to CURRENT_TIMESTAMP
>
> I try with a RULE but obtain only a loop, seem RULE aren't good to make
> such things, modify a statment on the same table it's related :(
>
> i look for a trigger but I suppose the same problem arise ...
>
> how i can solve the problem ???
>
> mhhh does i have to have a VIEW of parm ... called param2 without the ts
> field and make a rule on param2 that update param.ts ???
> seem a bit tricky :( ...
>
> thanks in advance ...