Add support for the pre-defined weak SYS_REFCURSOR

DECLARE

  c SYS_REFCURSOR;

  a INT;

BEGIN

  OPEN c FOR SELECT 1 FROM DUAL;

  FETCH c INTO a;

  CLOSE c;

  dbms_output.put_line(a); 

END;

/

CREATE TABLE t1 (a INT);

INSERT INTO t1 VALUES (10),(20);

CREATE FUNCTION f1 RETURN SYS_REFCURSOR AS

  c SYS_REFCURSOR;

BEGIN

  OPEN c FOR SELECT a FROM t1 ORDER BY a;

  RETURN c;

END;

/

CREATE PROCEDURE p1 AS

  a INT;

  c SYS_REFCURSOR DEFAULT f1();

BEGIN

  LOOP

    FETCH c INTO a;

    EXIT WHEN c%NOTFOUND;

    dbms_output.put_line(a);

  END LOOP;

  CLOSE c;

END;

/

CALL p1();

10

20

DECLARE

  TYPE storong_cursor IS REF CURSOR RETURN employees%ROWTYPE;  -- strong type - we'll be added later

  TYPE weak_cursor IS REF CURSOR;                              -- weak type - we'll be added later