车站光标练习_rowcount的问题.txt

orale培训教材包括了所有的sql说明和实例

--试分析以下存储过程的调用结果，其中存在什么问题？
create or replace procedure getstation(p_busno in varchar2) is 

  v_qidian bus.qidian%TYPE;
  v_zhongdian bus.zhongdian%TYPE;
  v_station busstation.station%TYPE;
  cursor c_station(busno varchar2) is select station from busstation
  where busno=p_busno;
begin
  
  
  select qidian,zhongdian into v_qidian ,v_zhongdian from bus where busno=p_busno;
  dbms_output.put_line ( p_busno || '路车 ' || '起点站：' || v_qidian || ',终点站: '|| v_zhongdian);

  open c_station(p_busno);
  
  --busstation中没有这次车的车站信息。光标对应集为空
  if c_station%rowcount =0 then 
    dbms_output.put_line('没有这次车的车站信息');
  end if;

  loop
    fetch c_station into v_station;
    if c_station%notfound then
 
      exit ;
    end if;
    dbms_output.put_line(v_station);

  end loop;
  close c_station;
end;