Qanday qilib protseduradan (REF CURSOR) qiymatni qaytarish mumkin?

Oracle PL/SQL-da, satrlar to'plamini qaytarish uchun tez-tez REF CURSOR ishlatiladi. Bu so'rov natijasiga ishora qiluvchi ko'rsatkich bo'lib, uni protsedura ichida ochish va chaqiruvchi kodga qaytarish mumkin.

REF CURSOR turidagi OUT parametr bilan protsedura misoli:

CREATE OR REPLACE PROCEDURE get_employees(p_dept_id IN NUMBER, p_refcur OUT SYS_REFCURSOR) AS
BEGIN
  OPEN p_refcur FOR
    SELECT employee_id, first_name, last_name
    FROM employees
    WHERE department_id = p_dept_id;
END;
/

PL/SQL blokidan chaqirish:

DECLARE
  rc SYS_REFCURSOR;
  emp_id employees.employee_id%TYPE;
  fname employees.first_name%TYPE;
  lname employees.last_name%TYPE;
BEGIN
  get_employees(10, rc);
  LOOP
    FETCH rc INTO emp_id, fname, lname;
    EXIT WHEN rc%NOTFOUND;
    DBMS_OUTPUT.PUT_LINE(emp_id || ' ' || fname || ' ' || lname);
  END LOOP;
  CLOSE rc;
END;
/

Shu tarzda, protsedura kerakli so'rov bilan REF CURSOR ochadi va chaqiruvchi kod undan ma'lumotlarni o'qiydi.