MySQL 상위 테이블에서 행을 삭제하면 어떻게 되나요?

mysql> Select * from Customer;
+----+--------+
| id | name   |
+----+--------+
| 1  | Gaurav |
| 2  | Raman  |
| 3  | Harshit|
| 4  | Aarav  |
+----+--------+
4 rows in set (0.00 sec)

mysql> Select * from orders;
+----------+----------+------+
| order_id | product  | id   |
+----------+----------+------+
| 100      | Notebook | 1    |
| 110      | Pen      | 1    |
| 120      | Book     | 2    |
| 130      | Charts   | 2    |
+----------+----------+------+
4 rows in set (0.00 sec)