休眠级联保存

Question

我对Hibernate有问题。 查看我的数据模型

我上课-“票” ...

@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name = "ticketComposition",
        joinColumns = { @JoinColumn(name = "ticketId")},
        inverseJoinColumns = { @JoinColumn(name = "tripsSiteId")})
private Set<TripsSite> tripsSites = new HashSet<TripsSite>();

当我试图保存新票时...

    Ticket ticket = new Ticket();
    User user = userService.findBySSO(userName);
    ticket.setUser(user);


    ticket.setTripsSites(new HashSet<>(tripsSites));

    persist(ticket);

我得到以下错误：com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException：不能添加或更新子行，外键约束失败（ sbb 。 ticketcomposition ，约束ticket外键（ ticketId ）参考文献ticket （ id ））

我该如何解决这个问题？

Answer 1

假设在TicketSite实体上定义了以下TicketSite ：

@ManyToMany(mappedBy="tripSites")
private Set<Trip> trips = new HashSet<Trip>();

持久化时，必须在@ManyToMany映射的两侧设置依赖@ManyToMany ：

Ticket ticket = new Ticket();
User user = userService.findBySSO(userName);
ticket.setUser(user);

ticket.setTripsSites(new HashSet<>(tripsSites));

for(TicketSite ticketSite: ticketSites){
   ticketSite.getTickets().add(ticket);
} 

persist(ticket);

我假设ticketSites集合先前已从数据库中检索到，并且在此事务处理方法开始之前已经存在。