Question

I need to take cursor fields names from another cursor like this:

FOR rec1 IN (SELECT * FROM table1) LOOP  
   FOR rec2 IN (SELECT * FROM table2) LOOP  
       IF rec1.[rec2.field_name] <> '*' THEN 
         ...                                          
       END IF;
   END LOOP;
END LOOP;

Answer 1

Oracle is really not designed for this kind of behavior. The only way I can think of to achieve this is to use dynamic PL/SQL to produce the functionality you’re looking for:

declare
  v_field_value varchar2(2000);
begin
  FOR rec1 IN (SELECT * FROM table1) LOOP  
     FOR rec2 IN (SELECT * FROM table2) LOOP  
         EXECUTE IMMEDIATE 'begin :value := :rec1.' 
                           || :rec2.field_name || '; end;' 
            USING OUT v_field_value, IN rec1;
         IF v_field_value  <> '*' THEN 
           ...                                          
         END IF;
     END LOOP;
  END LOOP;
end;

However, just because this approach can work doesn’t mean you should use it. If your field is not a string, for instance, Oracle will implicitly convert the value, which may result in a different value than what you expect. If this were my code, I would only use this as a last resort, after considering implementing the same functionality outside the database and redesigning the database’s structure to avoid the need for this type of code.

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Based on the comment the error mentioned in the comment, I’ve modified the code so to pass the records in using bind variables.