Hibernate继承映射
用户(父类)：
public class User implements Serializable {
private Integer id;
private String username;
private String password;
public User() {
super();
}
...此处省略get/set方法...
}
普通用户(子类)：
public class Member extends User {
private String name;
private String phone;
public Member() {
super();
}
...此处省略get/set方法...
}
管理员(子类)：
public class Manager extends User {
public Manager() {
super();
}
}
映射文件的配置
方式一(只建一张表)：
<hibernate-mapping package="day03.pm">
<class name="User" table="t_user1">
<id name="id">
<generator discriminator-value="me">
<property name="name"></property>
<property name="phone"></property>
</subclass>
<subclass name="Manager" discriminator-value="ma">
</subclass>
</class>
</hibernate-mapping>
mysql> desc t_user1;
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| status | varchar(255) | NO | | NULL | |
| username | varchar(255) | YES | | NULL | |
| password | varchar(255) | YES | | NULL | |
| name | varchar(255) | YES | | NULL | |
| phone | varchar(255) | YES | | NULL | |
+----------+--------------+------+-----+---------+----------------+
方式二(每个子类各建一张表)：
Member.hbm.xml
<hibernate-mapping package="day03.pm">
<import table="t_member1">
<id name="id">
<generator table="t_manager1">
<id name="id">
<generator table="t_user2">
<id name="id">
<generator table="t_member2">
<key column="user_id"></key>
<property name="name"></property>
<property name="phone"></property>
</joined-subclass>
<joined-subclass name="Manager" table="t_manager2">
<key column="user_id"></key>
</joined-subclass>
</class>
</hibernate-mapping>
mysql> desc t_user2;
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| username | varchar(255) | YES | | NULL | |
| password | varchar(255) | YES | | NULL | |
+----------+--------------+------+-----+---------+----------------+
mysql> desc t_member2;
+---------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+--------------+------+-----+---------+-------+
| user_id | int(11) | NO | PRI | NULL | |
| name | varchar(255) | YES | | NULL | |
| phone | varchar(255) | YES | | NULL | |
+---------+--------------+------+-----+---------+-------+
mysql> desc t_manager2;
+---------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+---------+------+-----+---------+-------+
| user_id | int(11) | NO | PRI | NULL | |
+---------+---------+------+-----+---------+-------+
