Hibernate级联保存

Question

我对Hibernate有点问题。请参阅my data model

我有课--“入场券”...

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

当我想存新票的时候...

    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:无法添加或更新子行:外键约束失败(sbb.ticketcomposition，constraint ticket外键(ticketId)引用ticket (id))

如何解决此问题？

Answer 1

假设您在TicketSite实体上定义了如下内容：

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

在持久化时，您必须在@ManyToMany映射的两端设置依赖项：

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集以前已经从数据库中检索过，并且在这个事务性方法启动之前已经持久化了。