创建触发器时提示表不存在？？？

create sequence product_log_seq minvalue 1 maxvalue 99999999
increment by 1
start with 1;create or replace trigger "product_log_tri"
  before insert
    on "i_product_log"
    referencing new as new old as old
    for each row
      begin
       select prodcut_log_seq.nextval into :new.pl_id from dual;
      end;
结果总是提示 "i_product_log"不存在表是实际存在的。请指教。