目的:

和ref cursor配合使用, 可以将游标变量分配给不同的SQL (而不是在declare中把游标给定死), 增加处理游标的灵活性

语法：

declare

type type_cursor is ref cursor [return 记录类型]; --使用 ref cursor 才能把游标分配给不同的SQL,return不能用在动态SQL中

v_cursor type_cursor ;

begin

OPEN v_cursor FOR select first_name, last_name from student;

OPEN v_cursor FOR ' select first_name,last_name from student where zip = :1 '

USING 绑定变量1;

open

静态SQL

cursor

cursor c1 is

open c1; fetch ... into ... ; close c1;

open for

静态SQL

ref cursor

type t_1 is ref cursor;

c2 t_1 ;

openc2 for;

open for using

动态SQL

type t_1 is ref cursor;

c2 t_1 ;

openc2 for using ... ;

例子1:

declare

type student_cur_type is ref CURSOR RETURN test_stu%ROWTYPE; --声明ref cursor类型, return类型固定

v_first_name test_stu.first_name%TYPE;

v_last_name test_stu.last_name%TYPE;

cur_stud student_cur_type;

begin

open cur_stud for select first_name,last_name from student ; --带return的ref cursor只能用在静态sql中

loop

fetch cur_stud into v_first_name, v_last_name;

exit when cur_stud%NOTFOUND;

dbms_output.put_line(v_first_name || ' ' || v_last_name);

end loop;

close cur_stud;

end;

例子2:

declare

v_zip varchar2(5) := '&sv_zip';

v_first_name varchar2(25);

v_last_name varchar2(25);

type student_cur_type is ref cursor; --声明ref cursor类型

student_cur student_cur_type; --student_cur是游标变量 / student_cur_type 是引用游标类型

begin

--2打开游标变量，让它指向一个动态select查询的结果集 ; 就是使用open for语句代替一般的open语句代开游标

open student_cur for 'select first_name,last_name ' from student where zip = :1'

using v_zip;

loop

fetch student_cur into v_first_name, v_last_name;

exit when student_cur%NOTFOUND;

dbms_output.put_line(v_first_name || ' ' || v_last_name);

end loop;

close student_cur;

end;

转载自：https://blog.csdn.net/crzzyracing/article/details/75336196