automatic update
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 ...
--
Alessandro GARDICH <gremlin@gremlin.it>
gremlin.it
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
Show quoted text
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 ...