/--创建一个单表的insert和update触发器：
 
Create or replace trigger biu_tabletest
  Before insert or update On tabletest
  for each row
begin
  if updating then
    update tabletest set ModifyTime = sysdate;
    elseif inserting then 
    insert into tabletest values(:field1, ...sysdate);
  end if;
end biu_tabletest;