How to use record to loop a ref cursor?

问题:

I want to write PL/SQL to test a function in a package. The package defines a cursor type

TYPE ref_cursor IS REF CURSOR;

I want to define a record based on that type.

My code is:

DECLARE
  cur PACKAGE_NAME.ref_cursor; 
  rec cur%ROWTYPE;

why is last line not correct?

回答1:

You can't define a record type based on a weakly-typed REF CURSOR. Since the cursor type defined in the package can be used to return data from an arbitrary query with arbitrary columns, the PL/SQL compiler can't determine an appropriate record type to fetch the data into.

If you know the actual data being returned from the function, you could declare a record of that type to fetch the data into. For example, if I declare a function that returns a weakly-typed cursor type but I know that the cursor really returns a cursor based on the EMP table, I can fetch the data into an EMP%ROWTYPE record (note that SYS_REFCURSOR is a system-defined weakly-typed REF CURSOR type)

create or replace function f1
  return sys_refcursor
is
  l_rc sys_refcursor;
begin
  open l_rc
   for select *
         from emp;
  return l_rc;
end;

declare
  l_rc sys_refcursor;
  l_emp emp%rowtype;
begin
  l_rc := f1;
  loop
    fetch l_rc into l_emp;
    exit when l_rc%notfound;
    dbms_output.put_line( l_emp.empno );
  end loop;
end;