Hibernate Insert正在嘗試更新標識列

Question

我是Hibernate的新手，嘗試在數據庫中保留對象時遇到一些問題。

@Entity
@Table(name="order")
public class Order implements Serializable {
    private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long number;

@Column(name="date")
private Timestamp date;

@Column(name="obs")
private String obss;

@OneToMany(fetch=FetchType.LAZY,cascade=CascadeType.ALL)
@JoinColumn(name="id", referencedColumnName="number")
private List <OrderDetail> orderDetail;

(...)

和OrderDetail類

@Entity
@Table(name="orderDetail")
public class OrderDetail implements Serializable {
private static final long serialVersionUID = 1L;

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

@Column(name="orderType")
private Long orderType;

(...)

當我嘗試將對象保存到數據庫時，出現以下錯誤：

Hibernate: 
    insert 
    into
        order
        (date, obs, rejectObs, pid, destiny, stateId, userId, version) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: 
    insert 
    into
        OrderDetail
        (boxId, date, digitalid, documentId, rejectObs, obs, orderId, stateId, orderType) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?,)
Hibernate: 
    update
        OrderDetail
    set
        id=? 
    where
        id=?
16/09/2014 11:50:03 org.hibernate.util.JDBCExceptionReporter logExceptions
WARNING: SQL Error: 8102, SQLState: S1000
16/09/2014 11:50:03 org.hibernate.util.JDBCExceptionReporter logExceptions
ERROR: Cannot update identity column 'id'.
16/09/2014 11:50:03 org.hibernate.event.def.AbstractFlushingEventListener performExecutions
GRAVE: Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: could not insert collection: [com.sa.ra.entities.Order.orderDetail#4252]

我不知道為什么Hibernate試圖更新orderDetail表。 有人知道發生了什么嗎？ 即時通訊使用SQL Server 2008和休眠3.5.0

Answer 1

有一個概念錯誤。

您要讓hibernate引用兩個實體，並將它們的ID用作彼此的主鍵和外鍵。 錯了

將兩個實體建立一對多關系的正確方法是在“許多”側添加一個外鍵，該外鍵必須引用“一個”類的主鍵。 這是數據庫問題，不僅是休眠限制。

您可以在此處閱讀有關Hibernate Collections的更多信息。

根據上述文檔，您必須按如下方式修改代碼：

“一個”方面

@Entity
@Table(name="order")
public class Order implements Serializable {
    [...]
    @OneToMany(targetEntity = OrderDetail.class, cascade = CascadeType.ALL, mappedBy = "order", fetch = FetchType.LAZY)
    private List <OrderDetail> orderDetail;
    [...]
}

然后，“許多”方面：

@Entity
@Table(name="orderDetail")
public class OrderDetail implements Serializable {
    [...]
    @ManyToOne(cascade = CascadeType.MERGE, fetch = FetchType.EAGER)
    @JoinColumn(name = "order_id", nullable = false)
    private Order order;
    [...]
}