Hibernate对象关系映射总结
public class Group{ private int id; private String name; private Set<User> users= new HashSet<User>();}@Entity@Table(name="t_jpa_group4") public class Group4{ private int id; private String name; private Set<User4> users= new HashSet<User4>();@OneToMany@JoinColumn(name="groupId") public Set<User4> getUsers(){ return users;}………………………………..}对应 t_jpa_user4如下：
public class User{ private int id; private String name;}
@Entity@Table(name="t_jpa_user4") public class User4{ private int id; private String name;……………………………………………..}一对多的@JoinColumn注解在“被控方”,即one的一方本表主键在对方表中做外键：外键的名称:groupid
订单
多对一单向关联
客户
多个订单对应一个客户：订单通过外键： customer_id能够找到自己的客户