有学生表student(sno,sname,sage),现对此表建立一个触发器。实现当对学生表删除一行数据时,则显示这一行的内容。其代码为 create or replace trigger tri_del_stu before delete on student for each row declare v_sno varchar(20); v_sname varchar(20); v_sage int; begin select :old.sno into v_sno from dual; dbms_output.put_line('sno:'||v_sno); select :old.sname into v_sname from dual; dbms_output.put_line('sname'||v_sname); select :old.sage into v_sage from dual; dbms_output.put_line('sage:'||v_sage); end; ( )