Running a function with a cursor output

Question

Hi All,
It sounds like this should be easy, but I can't get it to work! I'm trying to run or debug a function in JDev. The function simply calls a Java SP that returns a cursor. This all works fine and it runs in SPL Plus with no problems. The problem is that when I try to run it from within JDev I get presented with the PL/SQL block window, and nothing I do will let me view the contents of the cursor returned - mostly I just get errors and the code doesn't run at all.
The default code it generates is:
DECLARE
v_Return NULL;
BEGIN
v_Return := ALISI.POC.POCCALLSP();
-- Modify the code to output the variable
-- DBMS_OUTPUT.PUT_LINE('v_Return = ' || v_Return);
END;
I think this should be modified to say:
DECLARE
v_Return Types.ref_cursor;
BEGIN
v_Return := ALISI.POC.POCCALLSP();
-- Modify the code to output the variable
DBMS_OUTPUT.PUT_LINE('v_Return = ' || v_Return);
END;
But the DBMS_OUTPUT.PUT_LINE is expecting a string, not a cursor, and nothing I've tried (I've tried so many things I can't begin to list them - or remember them) will work.
Can anyone point out the error in my ways? Is it anything to do with the fact that I'm using a function and not a procedure? As you can probably tell I'm new to all this!
Many thanks,
John.

Answer 1

With "simple" variables, we are able to display the output using DBMS_OUTPUT. For composite variables (PL/SQL tables, PL/SQL records, cursors, etc), there's no good way for us to directly display the result. DBMS_OUTPUT.PUT_LINE can only take a "String", or something that can be converted to it, and unlike Java, not everything implements a toString method. We would expect in such cases that the user modify the code as desired to output the data.
That being said, you are actually encountering a bug here. With most datatypes that we can't display directly, we generally get enough information that we generate code that at least compiles and runs. I've logged a bug (3124777) to track this.
(For what it's worth, I've tried this in 9.0.5, only to discover that the functionality has regressed a bit to be even less correct than in 9.0.3.)
After the bug is fixed the output should look like this:
DECLARE
  v_Return Types.ref_cursor; -- assuming this is the name of your ref cursor type
BEGIN
  v_Return := ALISI.POC.POCCALLSP();
  -- Modify the code to output the variable
  -- DBMS_OUTPUT.PUT_LINE('v_Return = ' || v_Return);
END;The user would then need to modify the part that displays the output. In this example, it might go something like this:
DECLARE
  v_Return Types.ref_cursor; -- assuming this is the name of your ref cursor type
  v_Record v_Return%ROWTYPE;
BEGIN
  v_Return := ALISI.POC.POCCALLSP();
  -- Modify the code to output the variable
  LOOP
    FETCH v_Return INTO v_Record;
    EXIT WHEN v_Return%NOTFOUND;
    DBMS_OUTPUT.PUT_LINE (v_Record.employee_id || CHR(9) || v_Record.last_name
      || CHR(9) || v_Record.salary); -- replace with your field names
  END LOOP;
END;I hope this helps!
-- Brian