1. 自定义 ref cursor 和 sys_refcursor;
2. sys_refcursor 做为参数传递结果集;
3. ref cursor 做为参数传递结果集;

1. 自定义 ref cursor 和 sys_refcursor:

  declare
  type df_ref is ref cursor; --定义 ref cursor
  rf df_ref; --声明 rf 是df_ref
  ename varchar2(30);
 begin
  open rf for ‘select ename from emp‘;
  loop
   fetch rf into ename;
   dbms_output.put_line(ename);
  exit when rf%notfound;
 end loop;
 close rf; 
end;
/

sys_refcursor 不需要声明可以直接使用:

 declare
 reft sys_refcursor;
  begin
   open reft for ‘select * from emp‘;
  close  reft;  
 end;

sqlplus 中可以使用refcursor:

OPS$SYWU@sydb%11GR2>variable r refcursor;
OPS$SYWU@sydb%11GR2>exec open :r for ‘select * from emp‘;
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.00
OPS$SYWU@sydb%11GR2>print :r;
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10
14 rows selected.

2. sys_refcursor 做为参数传递结果集:

 create or replace procedure pro_getEmp(ref_rs out sys_refcursor)
 is
  begin
  open ref_rs for ‘select ename,empno from emp‘;
  ---不能在这里关闭
 end;
/

declare
refc sys_refcursor;
ename varchar2(30);
empno number;
begin
 pro_getEmp(ref_rs=>refc);
 loop
    fetch refc into ename,empno;
  dbms_output.put_line(ename||‘ ‘||empno);
 exit when refc%notfound;
 end loop;
end;
/ 

3. ref cursor 做为参数传递结果集:
   在包头定义 ref cursor:

create or replace package pk_cur 
  as 
  type df_cursor is ref cursor;
  
  function fun_emp return df_cursor;
 end;
/
 
 create or replace package body pk_cur
  is
  
   function fun_emp return df_cursor
     is
	fn_cursor df_cursor;
     begin
       open fn_cursor for ‘select * from emp‘;
     return fn_cursor;
   end;
end;
/
   
OPS$SYWU@sydb%11GR2>  select pk_cur.fun_emp from dual;
FUN_EMP
--------------------
CURSOR STATEMENT : 1
CURSOR STATEMENT : 1
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10
14 rows selected. 

Oracle ref cursor和sys_refcursor