CREATE TABLE employees AS SELECT * FROM hr.employees

Lots of Dynamic SQL!

CREATE OR REPLACE PROCEDURE dyn_binds (  
   col_in      IN     VARCHAR2,  
   value_in    IN     NUMBER,  
   total_out      OUT NUMBER,  
   id_in       IN     NUMBER)  
IS  
BEGIN  
   EXECUTE IMMEDIATE  
         'UPDATE employees SET '  
      || col_in  
      || ' = :val WHERE employee_id = :val'  
      USING value_in, id_in;  
  
   EXECUTE IMMEDIATE  
      'SELECT SUM (' || col_in || ') FROM employees'  
      INTO total_out;  
END; 

Incorrect Execution of Dynamic Block

DECLARE  
   l_total_salary   NUMBER;  
BEGIN  
   EXECUTE IMMEDIATE  
      'begin dyn_binds (:colname, :numval, :total_salary, :numval); end;'  
      USING IN 'salary',  
            IN 10000,  
            OUT l_total_salary,  
            IN 100;  
  
   DBMS_OUTPUT.put_line (l_total_salary);  
   ROLLBACK;  
END; 

Correct Execution of Dynamic Block

DECLARE  
   l_total_salary   NUMBER;  
BEGIN  
   EXECUTE IMMEDIATE  
      'begin dyn_binds (:colname, :numval, :total_salary, :numval); end;'  
      USING IN 'salary',  
            IN 10000,  
            OUT l_total_salary;  
  
   DBMS_OUTPUT.put_line (l_total_salary);  
   ROLLBACK;  
END; 

And This is Just a Mess

DECLARE  
   l_total_salary   NUMBER;  
BEGIN  
   EXECUTE IMMEDIATE  
      'begin dyn_binds (:colname, :numval, :numval, :numval); end;'  
      USING IN 'salary',  
            IN 10000;  
  
   DBMS_OUTPUT.put_line (l_total_salary);  
   ROLLBACK;  
END;