Question

我有两个实体，BidirectionalActivity（Parent）和Conversation（Child）。我想首先保存父级，一旦创建了我的对话或子级，我想更新父表并插入子级。

Below is my Schema

CREATE TABLE BIDIRECTIONAL_ACTIVITIES (
id bigint(20) NOT NULL AUTO_INCREMENT,
status VARCHAR(255) NOT NULL,
conversationId bigint(20),
PRIMARY KEY(id)
} 

create unique index index_conversationId on BIDIRECTIONAL_ACTIVITIES(conversationId);

CREATE TABLE CONVERSATION (
id bigint(20) NOT NULL AUTO_INCREMENT,
PRIMARY KEY(id),
FOREIGN KEY(id) REFERENCES BIDIRECTIONAL_ACTIVITIES(conversationId)
);

这是hibernate OneToOne中的映射：

@Entity
@Table(name="BIDIRECTIONAL_ACTIVITIES")
public class BidirectionalActivity implements Serializable{
    @Id
    @Column(name="id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;

    @Column(name="status")
    private String status;

   @OneToOne(fetch = FetchType.LAZY, mappedBy="bidirectionalActivity", cascade=CascadeType.ALL)
    @JoinColumn(name="conversationId")
    private Conversation conversation;
}


@Entity
@Table(name="CONVERSATION")
public class Conversation implements Serializable{
    @Id
    @Column(name="id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;

@OneToOne(fetch = FetchType.LAZY)
@PrimaryKeyJoinColumn
    private BidirectionalActivity bidirectionalActivity;
}

DAO Layer

public class BidirectionalActivityDAOImpl  implements BidirectionalActivityDAO {
 @Autowired
 private SessionFactory sessionFactory;
 @Override
 public void addBidirectionalActivity(BidirectionalActivity bidirectionalActivity) {
        Session session = this.sessionFactory.getCurrentSession();
        session.saveOrUpdate(bidirectionalActivity);
    }
}

服务层：

@Component
public class BidirectionalActivityServiceImpl implements BidirectionalActivityService {
    @Autowired
    BidirectionalActivityDAO BidirectionalActivityDAO;
    @Transactional
    @Override
    public Integer addBidirectionalActivity(BidirectionalActivity bidirectionalActivity) {
        return BidirectionalActivityDAO.addBidirectionalActivity(bidirectionalActivity);
    }

我的测试用例：

BidirectionalActivity bidirectionalActivity = new BidirectionalActivity();
bidirectionalActivity.setStatus("Active");
Integer persistedIdBiderectionalActivity = bidirectionalActivityService.addBidirectionalActivity(bidirectionalActivity);

Conversation conversation = new Conversation();
conversation.setBidirectionalActivity(persistedBidActvty);
        persistedBidActvty.setConversation(conversation);
   bidirectionalActivityService.addBidirectionalActivity(persistedBidActvty);

我原本期望hibernate首先在父表上执行insert语句，第二次它应该首先更新父表，然后再更新子表。然而，它只是在子表上第二次插入。

insert into CONVERSATION values ( )

我收到了错误：

Cannot add or update a child row: a foreign key constraint fails (`CONVERSATION`, CONSTRAINT `CONVERSATION_ibfk_1` FOREIGN KEY (`id`) REFERENCES `BIDIRECTIONAL_ACTIVITIES` (`conversationId`))

Answer 1

当新行进入CONVERSATION时，系统会为其分配一个auto_incrementing id。

您的外键约束通过确保列id中引用的表BIDIRECTIONAL_ACTIVITIES中的行中存在相同的conversationId来强制执行参照完整性（RI）。这样的行不存在。

也许您不希望设置 RI 。

也许这就是你真正想做的事情：

CREATE TABLE CONVERSATION
(
   id bigint(20) PRIMARY KEY,
   FOREIGN KEY(id) REFERENCES BIDIRECTIONAL_ACTIVITIES(conversationId)
);

简单地从其中删除AUTO_INCREMENT方面并手动输入在前一步骤中从某个列conversationId中的父插入确定的PK ID。

无论如何，你需要重新思考这一切。

插入子实体之前更新父实体

1 个答案: