--head
CREATE OR REPLACE package pkg_test_sql as 
type myrctype is ref cursor; 
function get_record(sql_str varchar2) return myrctype; 
end pkg_test_sql; 

--body
CREATE OR REPLACE package body pkg_test_sql as 
function get_record(sql_str varchar2) return myrctype is
rc myrctype;
begin 
if sql_str<>'' then 
  open rc for sql_str; --maybe error
end if; 

return rc; 
end get_record; 
end pkg_test_sql;