Using of oracle ref cursor

1、强类型游标： CREATE OR REPLACE PACKAGE strongly_typed ISTYPE return_cur IS REF CURSOR RETURN all_tables%ROWTYPE;PROCEDURE child(p_return_rec OUT return_cur);PROCEDURE parent(p_NumRecs PLS_INTEGER);END strongly_typed;/ CREATE OR REPLACE

1、强类型游标：

CREATE OR REPLACE PACKAGE strongly_typed IS

TYPE return_cur IS REF CURSOR RETURN all_tables%ROWTYPE;
PROCEDURE child(p_return_rec OUT return_cur);
PROCEDURE parent(p_NumRecs PLS_INTEGER);

END strongly_typed;
/

CREATE OR REPLACE PACKAGE BODY strongly_typed IS
PROCEDURE child(p_return_rec OUT return_cur) IS

BEGIN
  OPEN p_return_rec FOR 
  SELECT * FROM all_tables; 
END child;
--==================================================
PROCEDURE parent (p_NumRecs PLS_INTEGER) IS 
 p_retcur return_cur;
 at_rec   all_tables%ROWTYPE;
BEGIN
  child(p_retcur);

  FOR i IN 1 .. p_NumRecs
  LOOP
    FETCH p_retcur
    INTO at_rec;

    dbms_output.put_line(at_rec.table_name || 
    ' - ' || at_rec.tablespace_name || 
    ' - ' || TO_CHAR(at_rec.initial_extent) || 
    ' - ' || TO_CHAR(at_rec.next_extent));
  END LOOP;
END parent;
END strongly_typed;
/

set serveroutput on

exec strongly_typed.parent(1);
exec strongly_typed.parent(8);

2、弱类型游标：

CREATE OR REPLACE PROCEDURE child (
 p_NumRecs IN PLS_INTEGER,
 p_return_cur OUT SYS_REFCURSOR)
IS

BEGIN
  OPEN p_return_cur FOR
  'SELECT * FROM all_tables WHERE rownum <= ' || p_NumRecs ;
END child;
/

CREATE OR REPLACE PROCEDURE parent (pNumRecs VARCHAR2) IS
 p_retcur  SYS_REFCURSOR;
 at_rec    all_tables%ROWTYPE;
BEGIN
  child(pNumRecs, p_retcur);

  FOR i IN 1 .. pNumRecs
  LOOP
    FETCH p_retcur
    INTO at_rec;

    dbms_output.put_line(at_rec.table_name ||
    ' - ' || at_rec.tablespace_name ||
    ' - ' || TO_CHAR(at_rec.initial_extent) ||
    ' - ' || TO_CHAR(at_rec.next_extent));
  END LOOP;
END parent;
/

set serveroutput on

exec parent(1);
exec parent(17);

3、预定义游标变量：

CREATE TABLE employees (
empid   NUMBER(5),
empname VARCHAR2(30));

INSERT INTO employees (empid, empname) VALUES (1, 'Dan Morgan');
INSERT INTO employees (empid, empname) VALUES (2, 'Hans Forbrich');
INSERT INTO employees (empid, empname) VALUES (3, 'Caleb Small');
COMMIT;
CREATE OR REPLACE PROCEDURE pass_ref_cur(p_cursor SYS_REFCURSOR) IS

TYPE array_t IS TABLE OF VARCHAR2(4000)
INDEX BY BINARY_INTEGER;

rec_array array_t;

BEGIN
  FETCH p_cursor BULK COLLECT INTO rec_array;

  FOR i IN rec_array.FIRST .. rec_array.LAST
  LOOP
    dbms_output.put_line(rec_array(i));
  END LOOP;
END pass_ref_cur;
/
set serveroutput on

DECLARE
 rec_array SYS_REFCURSOR;
BEGIN
  OPEN rec_array FOR
  'SELECT empname FROM employees';

  pass_ref_cur(rec_array);
  CLOSE rec_array;
END;
/

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Dylan presents.