Unidirectional Many-to-One Mapping : Can't delete child data JPA Spring Boot

Question

In this scenario I use unidirectional @ManyToOne relationship like the following:

@Entity
public class Shop {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String shopName;

}

@Entity
public class Item {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne
    @OnDelete(action = OnDeleteAction.CASCADE)
    @JoinColumn(name = "shop_id")
    private Shop shop;

    private String itemName;

}

@Repository  
public interface ShopRepository extends JpaRepository<Shop, Long> {

}

@RestController
public class ShopController {
    
    @Autowired
    private ShopRepository shopRepository;
        
    @DeleteMapping("/deleteShop")
    private void deleteShop(@RequestParam Long id) {
        shopRepository.deleteById(id);
    }

}

When I try to delete the shop, I get below exception

org.postgresql.util.PSQLException: ERROR: update or delete on table "shop" violates foreign key constraint "fkedwdh6wdv6fqnyf914m5mt28i" on table "item"
  Detail: Key (id)=(2) is still referenced from table "item".

Expected:

It should delete child data item when I delete parent data shop.