一个简单记录用户修改表数据的触发器

create table t_temp
 (
old_sal number(7,2),
new_sal number(7,2),
who varchar2(20),
log timestamp
);

create or replace trigger update_emp_sal
 before update of sal on emp
 for each row
 begin
  insert into t_temp values(:old.sal,:new.sal,user,sysdate);
 end;
/