JPA/Hibernate 复合主外键多对一映射

Question

***已解决 - 已更新解决方案***

我有两张桌子：

通知 - 由 UserId + NotificationDetail 组成的复合键

notification_detail - 单个主键

我想使用 JPA 来持久化和读取这些对象，但无法让 ManyToOne 映射工作。

许多通知映射到一个notification_detail。

表格：

create table notification(
notification_user_id        int             not null,
notification_detail_id     int              not null,
notification_status_cd      int             not null,
primary key(notification_user_id, notification_detail_id),
constraint pkey_notification_detail foreign key(notification_detail_id) references notification_detail(notification_detail_id),
constraint pkey_notification_status_cd foreign key(notification_status_cd) references lk_notification_status(notification_status_id)
);

create table notification_detail (
notification_detail_id  int             auto_increment,
notification_type_cd    int             not null,
notification_message    varchar(50)     not null,
primary key(notification_detail_id),
constraint pkey_notification_type_cd foreign key(notification_type_cd) references lk_notification_type(notification_type_id)
);

***已解决和正确的 JPA 设置：***

class NotificationId implements Serializable {
    private static final long serialVersionUID = 1L;
    Integer notificationUserId;
    Integer details;
    public Integer getNotificationUserId() {
        return notificationUserId;
    }
    public void setNotificationUserId(Integer notificationUserId) {
        this.notificationUserId = notificationUserId;
    }
    public Integer getDetails() {
        return details;
    }
    public void setDetails(Integer details) {
        this.details = details;
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((details == null) ? 0 : details.hashCode());
        result = prime * result + ((notificationUserId == null) ? 0 : notificationUserId.hashCode());
        return result;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        NotificationId other = (NotificationId) obj;
        if (details == null) {
            if (other.details != null)
                return false;
        } else if (!details.equals(other.details))
            return false;
        if (notificationUserId == null) {
            if (other.notificationUserId != null)
                return false;
        } else if (!notificationUserId.equals(other.notificationUserId))
            return false;
        return true;
    }
}

@Entity
@Table(name="notification")
@IdClass(NotificationId.class)
public class Notification implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @NotNull
    private Integer notificationUserId;

    @Id
    @NotNull
    @ManyToOne(fetch=FetchType.LAZY, cascade=CascadeType.ALL)
    @JoinColumn(name="notification_detail_id")
    private NotificationDetail details;

    @NotNull
    private Integer notificationStatusCd;

    @NotNull
    private Integer updateUserId;

    public Integer getNotificationUserId() {
        return notificationUserId;
    }

    public void setNotificationUserId(Integer notificationUserId) {
        this.notificationUserId = notificationUserId;
    }

    public NotificationDetail getDetails() {
        return details;
    }

    public void setDetails(NotificationDetail details) {
        this.details = details;
    }

    public Integer getNotificationStatusCd() {
        return notificationStatusCd;
    }

    public void setNotificationStatusCd(Integer notificationStatusCd) {
        this.notificationStatusCd = notificationStatusCd;
    }

    public Integer getUpdateUserId() {
        return updateUserId;
    }

    public void setUpdateUserId(Integer updateUserId) {
        this.updateUserId = updateUserId;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((details == null) ? 0 : details.hashCode());
        result = prime * result + ((notificationStatusCd == null) ? 0 : notificationStatusCd.hashCode());
        result = prime * result + ((notificationUserId == null) ? 0 : notificationUserId.hashCode());
        result = prime * result + ((updateUserId == null) ? 0 : updateUserId.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Notification other = (Notification) obj;
        if (details == null) {
            if (other.details != null)
                return false;
        } else if (!details.equals(other.details))
            return false;
        if (notificationStatusCd == null) {
            if (other.notificationStatusCd != null)
                return false;
        } else if (!notificationStatusCd.equals(other.notificationStatusCd))
            return false;
        if (notificationUserId == null) {
            if (other.notificationUserId != null)
                return false;
        } else if (!notificationUserId.equals(other.notificationUserId))
            return false;
        if (updateUserId == null) {
            if (other.updateUserId != null)
                return false;
        } else if (!updateUserId.equals(other.updateUserId))
            return false;
        return true;
    }

}

@Entity
@Table(name="notification_detail")
public class NotificationDetail implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer notificationDetailId;

    @NotNull
    private Integer notificationTypeCd;

    @NotNull
    private String notificationMessage;

    @OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL, mappedBy="details")
    private Set<Notification> notifications;

    @NotNull
    private Integer updateUserId;

    public Integer getNotificationDetailId() {
        return notificationDetailId;
    }

    public void setNotificationDetailId(Integer notificationDetailId) {
        this.notificationDetailId = notificationDetailId;
    }

    public Integer getNotificationTypeCd() {
        return notificationTypeCd;
    }

    public void setNotificationTypeCd(Integer notificationTypeCd) {
        this.notificationTypeCd = notificationTypeCd;
    }

    public String getNotificationMessage() {
        return notificationMessage;
    }

    public void setNotificationMessage(String notificationMessage) {
        this.notificationMessage = notificationMessage;
    }

    public Set<Notification> getNotifications() {
        return notifications;
    }

    public void setNotifications(Set<Notification> notifications) {
        this.notifications = notifications;
    }

    public void addNotification(Notification notification){
        if(notifications == null)
            notifications = new HashSet<Notification>();
        notifications.add(notification);
    }

    public Integer getUpdateUserId() {
        return updateUserId;
    }

    public void setUpdateUserId(Integer updateUserId) {
        this.updateUserId = updateUserId;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((notificationDetailId == null) ? 0 : notificationDetailId.hashCode());
        result = prime * result + ((notificationMessage == null) ? 0 : notificationMessage.hashCode());
        result = prime * result + ((notificationTypeCd == null) ? 0 : notificationTypeCd.hashCode());
        result = prime * result + ((notifications == null) ? 0 : notifications.hashCode());
        result = prime * result + ((updateUserId == null) ? 0 : updateUserId.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        NotificationDetail other = (NotificationDetail) obj;
        if (notificationDetailId == null) {
            if (other.notificationDetailId != null)
                return false;
        } else if (!notificationDetailId.equals(other.notificationDetailId))
            return false;
        if (notificationMessage == null) {
            if (other.notificationMessage != null)
                return false;
        } else if (!notificationMessage.equals(other.notificationMessage))
            return false;
        if (notificationTypeCd == null) {
            if (other.notificationTypeCd != null)
                return false;
        } else if (!notificationTypeCd.equals(other.notificationTypeCd))
            return false;
        if (notifications == null) {
            if (other.notifications != null)
                return false;
        } else if (!notifications.equals(other.notifications))
            return false;
        if (updateUserId == null) {
            if (other.updateUserId != null)
                return false;
        } else if (!updateUserId.equals(other.updateUserId))
            return false;
        return true;
    }

}

JPA 用法：

NotificationDetail details = new NotificationDetail();
details.setMessage("Hello");
details.setTypeCd(NotificationTypeEnum.INFO);
detail.setUpdateUserId(userId);

Notification notif = new Notification();
notif.setNotifiedUserId(userId);
notif.setStatusCd(NotificationStatusEnum.UNREAD);
notif.setDetails(details);

notificationRepository.save(notif);

***此错误现已解决***：

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'notificati0_.details_notificationDetailId' in 'field list'

***原问题：***

我尝试了所有类型的不同配置。我能想到的最好的办法是我的情况很复杂，因为父对象“通知”有一个复合键“notification_detail_id”，它也是子对象的主键。这使得 Hibernate 很难先持久化 child，然后获取 key 并将其保存给 parent。

我意识到我的注释在某处不正确，但就是想不通。

Answer 1

看起来您正在处理“派生身份”。将您的类更改为如下所示：

class NotificationId implements Serializable {
    private static final long serialVersionUID = 1L;
    Integer notifiedUserId;
    Integer details;
    ...
}


@Entity
@IdClass(NotificationId.class)
@Table(name="notification")
public class Notification implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @NotNull
    @Column(name="notification_user_id")
    private Integer notifiedUserId;

    @Id
    @NotNull
    @ManyToOne(fetch=FetchType.LAZY, cascade=CascadeType.ALL)
    @JoinColumn(name="notification_detail_id")
    private NotificationDetail details;

    @NotNull
    @Column(name="notification_status_cd")
    private Integer statusCd;

    @Column(name="update_timestamp")
    private Date timestamp;

    ...
}

注意：

• NotificationId.notificationDetailId 已重命名为 details 以匹配 Notification 中的相应字段
• Notification.notificationDetailId 已被删除
• Notification.details 已被标记为 @Id

您的字段模型似乎暗示您应该对Notification 和User 之间的关系做同样的事情。

派生的身份在 JPA 2.1 规范的 2.4.1 节中进行了讨论。