我有以下实体:嵌入式ID设置为null
@Entity
@Table(name = "B_Message")
public class Message implements java.io.Serializable {
@Id
@GeneratedValue(generator = "app-uuid")
@Column(name = "MessageID", unique = true, nullable = false, length = 36, columnDefinition = "uniqueIdentifier")
private String id;
@OneToMany(cascade= {CascadeType.PERSIST, CascadeType.MERGE}, fetch = FetchType.LAZY, mappedBy = "message")
private Set<MessageReceiver> messageReceivers;
}
和
@Entity
@Table(name="B_MessageReceiver")
public class MessageReceiver implements java.io.Serializable {
@EmbeddedId
@AttributeOverrides({
@AttributeOverride(name="messageId", [email protected](name="MessageID", nullable=false, length=36, columnDefinition = "uniqueIdentifier")),
@AttributeOverride(name="accountabilityId", [email protected](name="AccID", nullable=false, length=36, columnDefinition = "uniqueIdentifier")) })
private MessageReceiverId id;
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="MessageID", nullable=false, insertable=false, updatable=false)
private Message message;
}
和
@Embeddable
public class MessageReceiverId implements java.io.Serializable {
@Column(name = "MessageID", nullable = false, length = 36)
private String messageId;
@Column(name = "AccID", nullable = false, length = 36)
private String accountabilityId;
}
而且我在下面的代码
Message message = new Message();
Set<MessageReceiver> messageReceivers = new HashSet<MessageReceiver>();
MessageReceiver messageReceiver = new MessageReceiver();
MessageReceiverId messageReceiverId = new MessageReceiverId();
messageReceiverId.setAccountabilityId(this.accountabilityModel.getId());
messageReceiver.setMessage(message);
messageReceiver.setId(messageReceiverId);
messageReceivers.add(messageReceiver);
messageManager.saveMessage(message);
使用它们
但是,当我想要合并Message
实体时,messageId
的MessageReceiverId
未被设置为 并向数据库发送空值。
的问题是,'message'是一个新创建的实体并且尚未保留,所以它没有为它自动创建任何消息ID。请注意,messageId应自动创建并合并到其他相关实体中。 – Soosh 2014-12-02 10:53:00
因此,在将其ID分配给'messageReceiverId'之前,必须将该消息对象保存在数据库中。 – 2014-12-02 12:01:42
是的,因为'messageId'是我自动生成的。 – Soosh 2014-12-02 12:08:11