Modularizing cursor operations v14
This example shows how you can modularize the various operations on cursor variables into separate programs.
The following procedure opens the given cursor variable with a SELECT command that retrieves all rows:
CREATE OR REPLACE PROCEDURE open_all_emp (
p_emp_refcur IN OUT SYS_REFCURSOR
)
IS
BEGIN
OPEN p_emp_refcur FOR SELECT empno, ename FROM emp;
END;This variation opens the given cursor variable with a SELECT command that retrieves all rows of a given department:
CREATE OR REPLACE PROCEDURE open_emp_by_dept (
p_emp_refcur IN OUT SYS_REFCURSOR,
p_deptno emp.deptno%TYPE
)
IS
BEGIN
OPEN p_emp_refcur FOR SELECT empno, ename FROM emp
WHERE deptno = p_deptno;
END;This variation opens the given cursor variable with a SELECT command that retrieves all rows but from a different table. The function’s return value is the opened cursor variable.
CREATE OR REPLACE FUNCTION open_dept (
p_dept_refcur IN OUT SYS_REFCURSOR
) RETURN SYS_REFCURSOR
IS
v_dept_refcur SYS_REFCURSOR;
BEGIN
v_dept_refcur := p_dept_refcur;
OPEN v_dept_refcur FOR SELECT deptno, dname FROM dept;
RETURN v_dept_refcur;
END;This procedure fetches and displays a cursor variable result set consisting of employee number and name:
CREATE OR REPLACE PROCEDURE fetch_emp (
p_emp_refcur IN OUT SYS_REFCURSOR
)
IS
v_empno emp.empno%TYPE;
v_ename emp.ename%TYPE;
BEGIN
DBMS_OUTPUT.PUT_LINE('EMPNO ENAME');
DBMS_OUTPUT.PUT_LINE('----- -------');
LOOP
FETCH p_emp_refcur INTO v_empno, v_ename;
EXIT WHEN p_emp_refcur%NOTFOUND;
DBMS_OUTPUT.PUT_LINE(v_empno || ' ' || v_ename);
END LOOP;
END;This procedure fetches and displays a cursor variable result set consisting of department number and name:
CREATE OR REPLACE PROCEDURE fetch_dept (
p_dept_refcur IN SYS_REFCURSOR
)
IS
v_deptno dept.deptno%TYPE;
v_dname dept.dname%TYPE;
BEGIN
DBMS_OUTPUT.PUT_LINE('DEPT DNAME');
DBMS_OUTPUT.PUT_LINE('---- ---------');
LOOP
FETCH p_dept_refcur INTO v_deptno, v_dname;
EXIT WHEN p_dept_refcur%NOTFOUND;
DBMS_OUTPUT.PUT_LINE(v_deptno || ' ' || v_dname);
END LOOP;
END;This procedure closes the given cursor variable:
CREATE OR REPLACE PROCEDURE close_refcur (
p_refcur IN OUT SYS_REFCURSOR
)
IS
BEGIN
CLOSE p_refcur;
END;This anonymous block executes all the previous programs:
DECLARE
gen_refcur SYS_REFCURSOR;
BEGIN
DBMS_OUTPUT.PUT_LINE('ALL EMPLOYEES');
open_all_emp(gen_refcur);
fetch_emp(gen_refcur);
DBMS_OUTPUT.PUT_LINE('****************');
DBMS_OUTPUT.PUT_LINE('EMPLOYEES IN DEPT #10');
open_emp_by_dept(gen_refcur, 10);
fetch_emp(gen_refcur);
DBMS_OUTPUT.PUT_LINE('****************');
DBMS_OUTPUT.PUT_LINE('DEPARTMENTS');
fetch_dept(open_dept(gen_refcur));
DBMS_OUTPUT.PUT_LINE('*****************');
close_refcur(gen_refcur);
END;The following is the output from the anonymous block:
ALL EMPLOYEES EMPNO ENAME ----- ------- 7369 SMITH 7499 ALLEN 7521 WARD 7566 JONES 7654 MARTIN 7698 BLAKE 7782 CLARK 7788 SCOTT 7839 KING 7844 TURNER 7876 ADAMS 7900 JAMES 7902 FORD 7934 MILLER **************** EMPLOYEES IN DEPT #10 EMPNO ENAME ----- ------- 7782 CLARK 7839 KING 7934 MILLER **************** DEPARTMENTS DEPT DNAME ---- --------- 10 ACCOUNTING 20 RESEARCH 30 SALES 40 OPERATIONS *****************