hibernate学习：级联查询

save the transient instance before flushing: com.hibernate.model.UserGroup

User u = new User();

u.setName("liuyanliang");

UserGroup g = new UserGroup();

g.setName("haha");

u.setGroup(g);

Session session = factory.getCurrentSession();

session.beginTransaction();

session.save(u);

session.getTransaction().commit();

默认情况下，save user的时候，不会自动关联user跟group的关系

需要在映射关系中加上级联操作

@ManyToOne(cascade = CascadeType.ALL)

private UserGroup group;

默认不产生任何级联

CascadeType.ALL

CascadeType.MERGE

CascadeType.PERSISTENCE

CascadeType.REFRESH

CascadeType.REMOVE