分别创建user,farm,user_general三张表
create table user(
uuid bigint not null auto_increment,
name varchar(100),
age int not null,
province varchar(100),
city varchar(100),
street varchar(100),
constraint pk_user primary key(uuid)
)charset=utf8 ENGINE=InnoDB; create table user_general(
uuid bigint not null,
realname varchar(10),
gender varchar(10),
birthday int,
height int,
weight int,
constraint pk_user_general primary key(uuid),
constraint fk_user_general foreign key(uuid) references user(uuid))charset=utf8 ENGINE=InnoDB; create table farm(
uuid bigint not null auto_increment,
user_id bigint,
name varchar(10),
constraint pk_farm primary key(uuid),
constraint fk_farm foreign key(user_id) references user(uuid))charset=utf8 ENGINE=InnoDB;
单向关联：
1.多对一映射(many to one)：
该标签在持久化类中属于多的一方配置；例如本例中farm即为多的一方。
重点是这段配置:
<many-to-one name="user" class="org.hibernate.tutorials.domain.User" column="user_id" cascade="save-update"/>
其中column对应表中的外键(另一张表的主键)，cascade设置为save-update后即可实现向数据库中级联修改
farm.hbm.xml配置:
<hibernate-mapping>
<class name="org.hibernate.tutorials.domain.Farm" table="farm">
<id name="uuid">
<generator class="native"/>
</id>
<property name="name"/>
<many-to-one name="user" class="org.hibernate.tutorials.domain.User" column="user_id" cascade="save-update"/>
</class>
</hibernate-mapping>
Farm对应的实体类:
public class Farm implements Serializable{
private int uuid;
private String name;
private User user;//农场所属用户
/**
* @return the uuid
*/
public int getUuid() {
return uuid;
}
/**
* @param uuid the uuid to set
*/
public void setUuid(int uuid) {
this.uuid = uuid;
}
/**
* @return the name
*/
public String getName() {
return name;
}
/**
* @param name the name to set
*/
public void setName(String name) {
this.name = name;
}
/**
* @return the user
*/
public User getUser() {
return user;
}
/**
* @param user the user to set
*/
public void setUser(User user) {
this.user = user;
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return "Farm [uuid=" + uuid + ", name=" + name + "]";
}
测试代码:
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
User user = new User();
user.setName("lucy");
Farm farm=new Farm();
farm.setName("test3");
farm.setUser(user);
Farm farm1=new Farm();
farm1.setName("test4");
farm1.setUser(user);
session.beginTransaction();
session.save(farm);
session.save(farm1);
session.getTransaction().commit();
2.一对一映射(分为2种情况：唯一外键和主键关联)
2.1：唯一外键：用的标签仍为many-to-one 区别是需要加unique="true"属性表示唯一映射，具体案例看这里
2.2主键关联映射:(一个字段同时是主键和外键(user和user_general))
<one-to-one name="user" class="org.hibernate.tutorials.domain.User" constrained="true"/> constrained="true"指明该类(UserGeneral)和关联的类(User)对应的表，通过外键引用对主键约束
UserGeneral.hbm.xml 配置
<hibernate-mapping>
<class name="org.hibernate.tutorials.domain.UserGeneral" table="user_general">
<id name="uuid">
<generator class="foreign">
<param name="property">user</param>
</generator>
</id>
<property name="realname"/>
<one-to-one name="user" class="org.hibernate.tutorials.domain.User" constrained="true"/>
</class>
</hibernate-mapping>
测试代码:
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
User user = new User();
user.setName("rrrrr");
UserGeneral ge=new UserGeneral();
ge.setUser(user);
ge.setRealname("cccccc");
session.beginTransaction();
session.save(ge);
session.getTransaction().commit();
参考：http://blog.csdn.net/zhang_xinxiu/article/details/25864763，http://blog.csdn.net/zhang_xinxiu/article/details/25950451