Can I pass an explicit cursor to a function/procedure for use in FOR loop?

Question

I have a procedure that performs some calculations on all records returned by a cursor. It looks a bit like this:

PROCEDURE do_calc(id table.id_column%TYPE)
IS
  CURSOR c IS
    SELECT col1, col2, col3
      FROM table
     WHERE ...;
BEGIN
  FOR r IN c LOOP
    -- do some complicated calculations using r.col1, r.col2, r.col3 etc.
  END LOOP;
END;

Now I have the case where I need to perform the exact same calculation on a different set of records that come from a different table. However, these have the same "shape" as in the above in example.

Is it possible to write a procedure that looks like this:

PROCEDURE do_calc2(c some_cursor_type)
IS
BEGIN
  FOR r IN c LOOP
    -- do the calc, knowing we have r.col1, r.col2, r.col3, etc.
  END LOOP;
END;

I know about SYS_REFCURSOR, but I was wondering if it was possible to use the much more convenient FOR ... LOOP syntax and implicit record type.

Answer 1

I had a similar problem, where I had two cursors that needed to be processed the same way, so this is how I figured it out.

DECLARE
   --Define our own rowType
   TYPE employeeRowType IS RECORD (
      f_name           VARCHAR2(30),
      l_name            VARCHAR2(30));
   --Define our ref cursor type
   --If we didn't need our own rowType, we could have this: RETURN employees%ROWTYPE
   TYPE empcurtyp IS REF CURSOR RETURN employeeRowType;

   --Processes the cursors
   PROCEDURE process_emp_cv (emp_cv IN empcurtyp) IS
      person employeeRowType;
   BEGIN
      LOOP
         FETCH emp_cv INTO person;
         EXIT WHEN emp_cv%NOTFOUND;
         DBMS_OUTPUT.PUT_LINE('Name = ' || person.f_name ||
                          ' ' || person.l_name);
      END LOOP;
   END;

   --Defines the cursors
   PROCEDURE mainProcedure IS
    emp empcurtyp;
   BEGIN
      OPEN emp FOR SELECT first_name, last_name FROM employees WHERE salary > 50000;
      process_emp_cv(emp);
      CLOSE emp;

      OPEN emp FOR SELECT first_name, last_name FROM kuren WHERE first_name LIKE 'J%';
      process_emp_cv(emp);
      CLOSE emp;
   END;

BEGIN
  mainProcedure;
END;
/

You can also use this if you want to bulk collect your cursors. You just need to change your helper procedure process_emp_cv; the rest can stay the same.

Using BULK COLLECT

 --Processes the cursors
   PROCEDURE process_emp_cv (emp_cv IN empcurtyp) IS
      TYPE t_employeeRowTable IS TABLE OF employeeRowType;
      employeeTable   t_employeeRowTable;
   BEGIN
      LOOP
         FETCH emp_cv BULK COLLECT INTO employeeTable LIMIT 50;
         FOR indx IN 1 .. employeeTable.Count
         LOOP
            DBMS_OUTPUT.PUT_LINE('Name = ' || employeeTable(indx).f_name ||
                          ' ' || employeeTable(indx).l_name);
         END LOOP;
         EXIT WHEN emp_cv%NOTFOUND;
      END LOOP;
   END;

Answer 2

Create a package.

Declare your cursor as package variable.

Use %rowtype to set function parameter type.

create or replace package test is
  cursor c is select 1 as one, 2 as two from dual;

  procedure test1;
  function test2(test_record c%ROWTYPE) return number;

end test;


create or replace package body test is
  procedure test1 is    
  begin
    for r in c loop      
      dbms_output.put_line(test2(r));
    end loop;
  end;

  function test2(test_record c%ROWTYPE) return number is
    l_summ number;
  begin
    l_summ := test_record.one + test_record.two;
    return l_summ;
  end;
end test;