Java JPA/Hibernate：映射实体中具有一对多关系的单个元素

我有以下表格：

TABLE Orders (
    ID BIGINT NOT NULL PRIMARY KEY,
    ... other columns ...
)

TABLE Order_States (
    ID         BIGINT NOT NULL PRIMARY KEY,
    Order_ID   BIGINT NOT NULL FOREIGN KEY REFERENCES Orders(ID),
    State_Type VARCHAR(30) NOT NULL,
    State_Date DATETIME NOT NULL,
    ... other columns ...
)

以及以下映射：

@Entity
@Table(name = "orders")
class Order {

    @Id
    @GeneratedValue
    private Long id;

    @OneToMany(mappedBy = "order")
    @OrderBy("stateDate DESC")
    private List<OrderState> orderStates

    public OrderState getCurrentState() {
        return orderStates.get(0);
    }

    public void setCurrentState(OrderState state) {
        state.setStateDate(new Date());
        orderStates.add(state);
    }

    ... other members ...
}

@Entity
@Table(name = "order_states")
class OrderState {

    @Id
    @GeneratedValue
    private Long id;

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

    @Enumerated(EnumType.STRING)
    @Column(name = "state_type")
    private StateType stateType;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "state_date")
    private Date stateDate;

    ... other members ...
}

---

您正在谈论的功能称为

软删除

。是通过使用

Hibernate

的注释

@SQLDelete

和

@Where

来执行这些操作的示例

然而，要使下面的代码正常工作是很困难的

@TakeFirst
private OrderState orderState

这样编码会更容易

@TakeFirst
private Set<OrderState> orderState // this will be a set containing one entry

@TakeFirst
私有集合orderState//这将是一个包含一个条目的集合

No。但是您可以将旧状态存储在一个rtable中，或者为旧状态添加一个包含true的“old”列，并使用注释。您是否能够获得此问题的优雅解决方案？

@TakeFirst
private Set<OrderState> orderState // this will be a set containing one entry