ALTER TABLE order
ADD CONSTRATINT fk_created_by FOREIGN KEY (instructor_created_by)
REFERENCES instructor(instructor_id);

ALTER TABLE order
ADD CONSTRATINT fk_touched_by FOREIGN KEY (student_touched_by)
REFERENCES student(student_id);

,CONSTRAINT pk_order_id PRIMARY KEY (order_id)
REFERENCES order_id (order_id)
,CONSTRAINT fk_customer_id FOREIGN KEY (customer_id)
REFERENCES customer_id (customer_id)
CONSTRATINT fk_created_by FOREIGN KEY (instructor_created_by)
REFERENCES instructor(instructor_id);
CONSTRATINT fk_touched_by FOREIGN KEY (student_touched_by)
REFERENCES student(student_id))

,CONSTRAINT pk_order_id PRIMARY KEY (order_id)
REFERENCES order_id (order_id)
,CONSTRAINT fk_customer_id FOREIGN KEY (customer_id)
REFERENCES customer_id (customer_id)