INVALID CURSOR - Anonymous Block calling Cursor in function

Question

I am getting an error when trying to call my cursor.
CREATE OR REPLACE PACKAGE tax_update
AS
TYPE gencur IS ref cursor;
FUNCTION tax_sf
   p_state IN bb_tax.state%type,
   p_thecursor IN OUT gencur
RETURN NUMBER;
END;
CREATE OR REPLACE PACKAGE BODY tax_update
AS
FUNCTION tax_sf
   p_state IN bb_tax.state%type,
   p_thecursor IN OUT gencur
RETURN NUMBER
  IS
  lv_taxrate NUMBER;
BEGIN
  OPEN p_thecursor FOR
   SELECT taxrate
   FROM bb_tax
   WHERE state = p_state;
  RETURN lv_taxrate;
END;
END;
DECLARE
  tax_cur tax_update.gencur;
  rec_tax bb_tax%rowtype;
BEGIN
LOOP
  FETCH tax_cur INTO rec_tax;
   EXIT WHEN tax_cur%NOTFOUND;
    DBMS_OUTPUT.PUT_LINE(rec_tax.taxrate);
END LOOP;
END;
DECLARE
ERROR at line 1:
ORA-01001: invalid cursor
ORA-06512: at line 6Assignment is to create a package that will hold tax rates by state in a packaged cursor. The package will contain a function that can receive a 2 character state abbr. as an argument and find a match in the cursor and return the tax rate for tha tstate. An anonymous block will test the function with state of NC.
Can anyone assist?

Answer 1

You would need to call the function to open the cursor before you try to fetch from the cursor
DECLARE
  tax_cur tax_update.gencur;
  rec_tax bb_tax%rowtype;
  l_some_number number;
BEGIN
  l_some_number :=  tax_update.tax_sf( <<some state parameter>>, tax_cur );
  LOOP
    FETCH tax_cur INTO rec_tax;
    EXIT WHEN tax_cur%NOTFOUND;
    DBMS_OUTPUT.PUT_LINE(rec_tax.taxrate);
  END LOOP;
END;A couple of points, though.
1) Your function returns a NUMBER but that NUMBER will always be NULL. It seems rather unlikely that this is really what you want. It would seem to make more sense for the function to return the cursor rather than returning a superfluous number.
2) Your function requires a `bb_tax.state%type` parameter. But your anonymous block doesn't seem to have any concept of a state so I'm not sure what you want to pass in there.
3) Looking at the code, it seems a bit odd that your cursor returns a single column of data. If a state can have multiple rates, wouldn't you need to select some additional criteria in order to figure out which sort of tax each row represents or to otherwise differentiate different rows? If a state can only have a single tax rate, it makes no sense to open a cursor that is only going to ever return a single row.
4) There is no need to declare your own weak ref cursor type (tax_update.gencur). You can just use the Oracle built-in type SYS_REFCURSOR.
Justin