Simple database logging with triggers

gistfile1.sql

-- Simple database logging to a table via Triggers (PostgresSQL)

-- Create tables --
create table tbl1 ( id integer, name varchar(20), ssn  integer );
create table tbl1_logcopy ( modified date, id integer, name varchar(20), ssn  integer );

-- Populate --
insert into tbl1 values ( 1, '123', 1000);
insert into tbl1 values ( 2, '234', 2000);
insert into tbl1 values ( 3, '345', 3000);
insert into tbl1 values ( 4, '456', 4000);
insert into tbl1 values ( 5, '567', 5000);
insert into tbl1 values ( 6, '678', 6000);
insert into tbl1 values ( 7, '789', 7000);

-- Create Trigger Function --
CREATE OR REPLACE FUNCTION log_into_tbl1_logcopy() RETURNS TRIGGER AS $$ 
BEGIN
  INSERT INTO tbl1_logcopy VALUES ( now() , OLD.id, OLD.name, OLD.ssn );
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;  

-- Activate trigger --
CREATE TRIGGER log_silently
BEFORE UPDATE OR DELETE ON tbl1
FOR EACH ROW EXECUTE PROCEDURE log_into_tbl1_logcopy();

-- Do update and see what happens with tbl1_logcopy ;-)
update tbl1 set id=1001 where id=1;