fetch from function returning a ref cursor to record

Question

I have a function in a package that returns a REF CURSOR to a RECORD. I am trying to call this function from a code block. The calling code looks like this:

declare      
   a_record package_name.record_name; 
   cursor c_symbols is select package_name.function_name('argument') from dual;

begin 
   open c_symbols;   
   loop            
        fetch c_symbols into a_record;
        exit when c_symbols%notfound;              
   end loop;
   close c_symbols; 
end;

The function declaration as part of package_name looks something like this:

TYPE record_name IS RECORD(
      field_a       varchar2(20);
);

TYPE record_cursor IS REF CURSOR RETURN record_name;

FUNCTION getsymbols(argument IN varchar2) return record_cursor;

When I try to run the calling code block, I get the exception: PLS-00386: type mismatch found at 'EXAMPLE_SYMBOLS' between FETCH cursor and INTO variables.

What should the type of a_record be and how can I access individual elements of the record I am fetching(of type record_name)?

Answer 1

I suspect that you think that your cursor should be fetching rows from the REFCURSOR. It's not. The REFCURSOR is itself a cursor, you don't use another cursor to select from it.

What your current cursor is doing is fetching a single row, with a single column, containing the result of the function call. Which is a record_cursor not a record_name, so you get a type mismatch.

I suspect what you really want to do is something like this:

declare
  symbol_cursor  package_name.record_cursor;
  symbol_record  package_name.record_name;
begin
  symbol_cursor := package_name.function_name('argument');
  loop
    fetch symbol_cursor into symbol_record;
    exit when symbol_cursor%notfound;

    -- Do something with each record here, e.g.:
    dbms_output.put_line( symbol_record.field_a );

  end loop;

  CLOSE symbol_cursor;

end;

Answer 2

The function returns a record_cursor, so I would expect a_record should also be a record_cursor. However, it is not clear why you are returning a ref cursor anyway - why can't the function return a record_name type instead?

Answer 3

The pl/sql block to read out the ref cursor looks a bit strange to me. Oracle might not be able to match the type of your cursor c_symbols with the type package_name.record_cursor.

Suggestion:

• change the declaration of c_symbols to "c_symbols package_name.record_cursor"
• replace the statement "open c_symbols" with "c_symbols := package_name.function_name('argument')"

As long as the called function really does return a cursor, that should work. Else, you might want to post actual source code.