Question

我在网上尝试了其他所有选项。但无法同时在Tickets和Messages表（外键映射）中成功插入记录。

你能辨别出什么是错的吗？当我运行代码时，我只在ticket表中获取记录，而不是在messages表中。

以下是Ticket.class

@Entity
@Table(name = "ticket")
public class Ticket {

    @Id
    @Column(name = "ticket_id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    int ticket_id;

    @Column(name = "ticket_desc")
    String ticket_desc;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "ticket")
    Set<Message> message = new HashSet<Message>();

    public int getTicket_id() {
        return ticket_id;
    }

    public void setTicket_id(int ticket_id) {
        this.ticket_id = ticket_id;
    }

    public String getTicket_desc() {
        return ticket_desc;
    }

    public void setTicket_desc(String ticket_desc) {
        this.ticket_desc = ticket_desc;
    }

    public Set<Message> getMessage() {
        return message;
    }

    public void setMessage(Set<Message> message) {
        this.message = message;
    }

}

下面是Message.class

@Entity
@Table(name = "message")
public class Message {

    @Id
    @Column(name = "message_id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int message_id;

    @Column(name = "ticket_id")
    private int ticket_id;

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

    @JoinColumn(name = "ticket_id", insertable = false, updatable = false)
    @ManyToOne(cascade=CascadeType.ALL) 
    private Ticket ticket;

    public Ticket getTicket() {
        return ticket;
    }

    public void setTicket(Ticket ticket) {
        this.ticket = ticket;
    }

    public int getMessage_id() {
        return message_id;
    }

    public void setMessage_id(int message_id) {
        this.message_id = message_id;
    }

    public int getTicket_id() {
        return ticket_id;
    }

    public void setTicket_id(int ticket_id) {
        this.ticket_id = ticket_id;
    }

    public String getMessage_text() {
        return message_text;
    }

    public void setMessage_text(String message_text) {
        this.message_text = message_text;
    }

}

以下是test（）

 public static void test() {
        Session session = HibernateSession.getHibernateSession();
        Transaction t = session.beginTransaction();

        Ticket ticket = new Ticket();
        ticket.setTicket_desc("ticket description 2");

        Set<Message> messages = new HashSet<Message>();

        Message message = new Message();
        message.setMessage_text("This is message text 2");
        message.setTicket(ticket);
        messages.add(message);

        ticket.setMessage(messages);

        session.persist(ticket);
        t.commit();
    }

你能辨别出什么是错的吗？当我运行代码时，我只在ticket表中获取记录，而不是在messages表中。

Answer 1

原因是您的映射不会级联持久操作，请参阅：

@OneToMany(fetch = FetchType.LAZY, mappedBy = "ticket")
Set<Message> message = new HashSet<Message>();

如果您希望进行级联操作，则需要指定

@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "ticket")
Set<Message> message = new HashSet<Message>();

级联操作非常有用，但要注意它们的潜在副作用，特别是如果您修改了{* 1}}，而您不打算将操作级联到Ticket。

如果要分别管理Message和Message的持久性状态，则需要修改业务逻辑代码以保留Ticket，然后保留Message。

为什么hibernate不会在子表中插入？

1 个答案: