oracle中REF Cursor用法

/*conn scott/tiger*/
 Declare
  Type MyRefCur  IS  Ref  Cursor;
  vRefCur MyRefCur;
  vtemp  vRefCur%RowType;
 Begin
  Case(&n)
   When  1 Then Open vRefCur  For Select   *   from emp;
   When  2 Then Open vRefCur  For Select   *   from dept;
   Else
    Open vRefCur  For Select   eno,  ename  from emp Where JOB = 'CLERK';
  End Case;
  Close  vRefCur;
 End;

--作为函数返回值
create or replace function returnacursor return sys_refcursor
is
   v_csr sys_refcursor;
begin
    open v_csr for select a1 from test3;
    return v_csr;
end;
/

declare
c sys_refcursor;
a1 char(2);
begin
  c:=returnacursor;
  loop
    fetch c into a1;
    exit when c%notfound;
    dbms_output.put_line(a1);
  end loop;
  close c;
end;
/

--作为参数
create or replace procedure proc_ref_cursor (rc in sys_refcursor) as
  v_a number;
  v_b varchar2(10);
 
begin
  loop
    fetch rc into v_a, v_b;
    exit when rc%notfound;
    dbms_output.put_line(v_a || ' ' || v_b);
  end loop;
end;
/

declare
v_rc sys_refcursor;
begin
  open v_rc for
  select a1,a2 from test3;
  proc_ref_cursor(v_rc);
  close v_rc;
end;
/

CREATE OR REPLACE PACKAGE BODY CURSPKG AS
    PROCEDURE OPEN_ONE_CURSOR (N_EMPNO IN NUMBER,
                               IO_CURSOR IN OUT T_CURSOR)
    IS
        V_CURSOR T_CURSOR;
    BEGIN
        IF N_EMPNO <> 0
        THEN
             OPEN V_CURSOR FOR
             SELECT EMP.EMPNO, EMP.ENAME, DEPT.DEPTNO, DEPT.DNAME
                  FROM EMP, DEPT
                  WHERE EMP.DEPTNO = DEPT.DEPTNO
                  AND EMP.EMPNO = N_EMPNO;

        ELSE
             OPEN V_CURSOR FOR
             SELECT EMP.EMPNO, EMP.ENAME, DEPT.DEPTNO, DEPT.DNAME
                  FROM EMP, DEPT
                  WHERE EMP.DEPTNO = DEPT.DEPTNO;

        END IF;
        IO_CURSOR := V_CURSOR;
    END OPEN_ONE_CURSOR;

    PROCEDURE OPEN_TWO_CURSORS (EMPCURSOR OUT T_CURSOR,
                                DEPTCURSOR OUT T_CURSOR)
    IS
        V_CURSOR1 T_CURSOR;
        V_CURSOR2 T_CURSOR;
    BEGIN
        OPEN V_CURSOR1 FOR SELECT * FROM EMP;
        OPEN V_CURSOR2 FOR SELECT * FROM DEPT;
        EMPCURSOR  := V_CURSOR1;
        DEPTCURSOR := V_CURSOR2;
    END OPEN_TWO_CURSORS;
END CURSPKG;
/

SQL> desc emp
Name Null? Type
----------------------------------------- -------- ----------------------------
EMPNO NOT NULL NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(7,2)
DEPTNO NUMBER(2)

使用ref cursor获得结果集输出：

SQL> set serveroutput on
SQL> DECLARE
2 TYPE mytable IS TABLE OF emp%ROWTYPE;
3 l_data mytable;
4 l_refc sys_refcursor;
5 BEGIN
6 OPEN l_refc FOR
7 SELECT empno, ename, job, mgr, hiredate, sal, comm, deptno FROM emp;
8
9 FETCH l_refc BULK COLLECT INTO l_data;
10
11 CLOSE l_refc;
12
13 FOR i IN 1 .. l_data.COUNT
14 LOOP
15 DBMS_OUTPUT.put_line ( l_data (i).ename
16 || ' was hired since '
17 || l_data (i).hiredate
18 );
19 END LOOP;
20 END;
21 /
SMITH was hired since 17-DEC-80
ALLEN was hired since 20-FEB-81
WARD was hired since 22-FEB-81
JONES was hired since 02-APR-81
MARTIN was hired since 28-SEP-81
BLAKE was hired since 01-MAY-81
CLARK was hired since 09-JUN-81
SCOTT was hired since 19-APR-87
KING was hired since 17-NOV-81
TURNER was hired since 08-SEP-81
ADAMS was hired since 23-MAY-87
JAMES was hired since 03-DEC-81
FORD was hired since 03-DEC-81
MILLER was hired since 23-JAN-82

PL/SQL procedure successfully completed.

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