创建触发器tri_pt产生错误：

            SQL> create or replace trigger tri_pt

                2   after delete on student2

               3   declare

                4        v_dept_id number;

                5   begin

                6         v_dept_id := :old.dept_id

                7    end;

                8    /

            Error: ora-04082: NEW or OLD references not allowed in table level triggers

【原因】

        :new 和 :old 适用于行级触发器。本例中定义的触发器不是行级触发器。

【解决方法】

        将触发器改为行级触发器

               SQL> create or replace trigger tri_pt

                2   after delete on student2

                3   for   each row           ------------添加此行脚本  

               4   declare

                5        v_dept_id number;

                6   begin

                7         v_dept_id := :old.dept_id

                8    end;

                9    /