需求: 用戶與身份證信息
一條用戶記錄對應一條身份證信息! 一對一的關係!
1.基於外鍵的映射
javabean:
// 身份證
public class IdCard {
// 身份證號(主鍵)
private String cardNum;// 對象唯一表示(Object Identified, OID)
private String place; // 身份證地址
// 身份證與用戶,一對一的關係
private User user;
// 用戶
public class User {
private int userId;
private String userName;
// 用戶與身份證信息, 一對一關係
private IdCard idCard;
User.hbm.xml配置
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="c_one2one">
<class name="User" table="t_user">
<id name="userId">
<generator class="native"></generator>
</id>
<property name="userName" length="20"></property>
<!--
一對一映射: 沒有外鍵方
-->
<one-to-one name="idCard" class="IdCard"></one-to-one>
</class>
</hibernate-mapping>
IdCard.hbm.xml配置
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="c_one2one">
<class name="IdCard" table="t_IdCard">
<id name="cardNum">
<generator class="assigned"></generator>
</id>
<property name="place" length="20"></property>
<!--
一對一映射,有外鍵方
unique="true" 給外鍵字段添加唯一約束
-->
<many-to-one name="user" unique="true" column="user_id" class="User" cascade="save-update"></many-to-one>
</class>
</hibernate-mapping>
2.基於主鍵的映射
javabean
// 身份證
public class IdCard {
// 身份證號(主鍵)
private String cardNum;// 對象唯一表示(Object Identified, OID)
private String place; // 身份證地址
// 身份證與用戶,一對一的關係
private User user;
// 用戶
public class User {
private int userId;
private String userName;
// 用戶與身份證信息, 一對一關係
private IdCard idCard;
hbm.xml配置
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="cn.itcast.c_one2one">
<class name="IdCard" table="t_IdCard">
<id name="cardNum">
<generator class="assigned"></generator>
</id>
<property name="place" length="20"></property>
<!--
一對一映射,有外鍵方
unique="true" 給外鍵字段添加唯一約束
-->
<many-to-one name="user" unique="true" column="user_id" class="User" cascade="save-update"></many-to-one>
</class>
</hibernate-mapping>
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="cn.itcast.c_one2one">
<class name="User" table="t_user">
<id name="userId">
<generator class="native"></generator>
</id>
<property name="userName" length="20"></property>
<!--
一對一映射: 沒有外鍵方
-->
<one-to-one name="idCard" class="IdCard"></one-to-one>
</class>
</hibernate-mapping>