Spring deleteBy 仅适用于 @Query

Question

派生的 DeleteBy 查询不起作用。但是findBy 并使用@Query 删除有效。

我尝试添加@Modifying和@Transactional，我将返回类型更改为Long、List<OrderItem>、void。

这是我的 CrudRepository 接口，Order 和 OrderItem 类：

public interface OrderItemRepository extends CrudRepository<OrderItem, Long> {
    List<OrderItem> findByOrderAndItem_ItemGroup(Order order, ItemGroup itemGroup);

    @Transactional
    Long deleteByOrder(Order order);

    @Modifying
    @Query("delete from OrderItem o where o.order = ?1")
    Integer deleteByOrderQuery(Order order);
}

@Entity
@Table(name = "t_order_items")
public class OrderItem {
    @GeneratedValue
    @Id
    private Integer id;

    @Column(name="itemcount")
    private Integer itemCount;

    @OneToOne()
    @JoinColumn(name="item_id")
    private Item item;

    @ManyToOne
    @JoinColumn(name = "oder_id")
    private Order order;
}

@Entity
@Table(name = "t_orders")
public class Order implements Serializable {
    @GeneratedValue
    @Id
    private Integer id;

    @Column(name = "orderdate")
    private LocalDate orderDate;

    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.REMOVE, mappedBy = "order")
    private List<OrderItem> orderItems;
}

我已阅读文档http://docs.spring.io/spring-data/jpa/docs/current/reference/html/，但 deleteBy 并没有什么特别之处。

Answer 1

问题出在CascadeType.ALL。 当我将其更改为 CascadeType.REMOVE 时，一切正常。 正确答案是：

@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.REMOVE, mappedBy = "order")
private List<OrderItem> orderItems;

Answer 2

在您提供的网址中可以阅读：

public interface UserRepository extends CrudRepository<User, Long> {

  Long deleteByLastname(String lastname);
  List<User> removeByLastname(String lastname);
}

您的问题可能是方法的返回类型错误。 Delete 方法返回被删除项的 ID！

代码可能是：

public interface OrderItemRepository extends JpaRepository<OrderItem, Long> {
    List<OrderItem> findByOrderAndItem_ItemGroup(Order order, ItemGroup itemGroup);

    Long deleteByOrder(Order order);

    @Modifying
    @Query("delete from OrderItem o where o.order = ?1")
    Integer deleteByOrderQuery(Order order);
}