ORACLE 游标的4种应用方法

--1.普通cursor
set serveroutput on;
declare 
   num1 number;
   num2 number;
   cursor SEQ is select SEQ,JCXM from test;
begin
    OPEN SEQ;   
    loop
        fetch SEQ into num1, num2;
         dbms_output.put_line(num1||','||num2);
        exit when SEQ%NOTFOUND;
    end loop;
    CLOSE SEQ;
    Exception
    When others then
       Rollback;
end;
--2.使用FOR循环的游标1;

 declare 
   num1 number;
   num2 number;
   cursor SEQ is select SEQ,JCXM from test;
begin
    
    for seq_r in SEQ loop
     dbms_output.put_line(seq_r.seq||','||seq_r.jcxm);
     
    end loop;
    Exception
    When others then
       Rollback;
end;
--3.使用FOR循环的游标2;

 declare 
   num1 number;
   num2 number;
   cursor SEQ is select SEQ,JCXM from test;
begin
    for seq_r in (select SEQ,JCXM from test ) loop
    dbms_output.put_line(seq_r.seq||','||seq_r.jcxm);
    END loop;
    Exception
    When others then
       Rollback;
end;
--4.带参数的游标

 declare 
   num1 number;
   num2 number;
   cursor SEQ(seqNum number ) is select SEQ,JCXM from test where seq = seqNum; 
begin
    
    for seq_r in SEQ(11) loop
    dbms_output.put_line(seq_r.seq||','||seq_r.jcxm);
    END loop;
    Exception
    When others then
       Rollback;
end;

  游标for循环的优点是：用户不需要打开游标，去数据，测试数据的存在，关闭游标或者定义存放数据的变量。

 缺点就不知道了，会不会影响速度呢？