hibernate详解（八）基于主键映射的一对一关联关系

sql语句：

 /* 基于主键的映射 */
 CREATE TABLE t_person_pk
 (
    id NUMBER(10) PRIMARY KEY,
    name VARCHAR2(20) NOT NULL,
    gender VARCHAR2(10),
    age NUMBER(3) CHECK(age BETWEEN 1 AND 100)
 );

CREATE TABLE t_passport_pk
 (
    id NUMBER(10) PRIMARY KEY REFERENCES t_person_pk(id),
    bh VARCHAR2(20) NOT NULL UNIQUE
 );
 
 CREATE SEQUENCE t_person_pk_seq
 START WITH 1
 INCREMENT BY 1;

Person_PK.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.iotek.basic.association.one2one.pojo">
    <class name="Person" table="T_PERSON_PK">
        <id name="id" column="ID" type="long">
            <generator class="sequence">
                <param name="sequence">t_person_fk_seq</param>
            </generator>
        </id>
        
        <property name="name" type="string" column="NAME"/>
        <property name="age" type="integer" column="AGE"/>
        <property name="gender" type="string" column="GENDER"/>
        <one-to-one name="passport" class="Passport" cascade="all"/>
    </class>
</hibernate-mapping>

Passport_PK.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.iotek.basic.association.one2one.pojo">
    <class name="Passport" table="T_PASSPORT_PK">
        <id name="id" column="ID" type="long">
            <generator class="foreign">
                <param name="property">person</param>
            </generator>
        </id>
        
        <property name="bh" type="string" column="BH"/>
        <one-to-one name="person" class="Person"></one-to-one>
    </class>
</hibernate-mapping>

hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory>
        <!-- property 元素用于配置Hibernate中的属性 键:值 -->
        
          <!-- hibernate.connection.driver_class : 连接数据库的驱动  -->
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        
          <!-- hibernate.connection.url : 连接数据库的地址,路径 -->
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
        
          <!-- hibernate.connection.username : 连接数据库的用户名 -->
        <property name="connection.username">system</property>
        
          <!-- hibernate.connection.password : 连接数据库的密码 -->
        <property name="connection.password">root</property>
        
          <!-- show_sql: 操作数据库时,会 向控制台打印sql语句 -->
        <property name="show_sql">true</property>
        
          <!-- 数据库方言配置 org.hibernate.dialect.Oracle10gDialect (选择最短的)-->
        <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
        
          <!-- 加载配置文件的pojo类，否则找不到，报错, unknow entity -->
        <mapping resource="com/iotek/basic/pojo/Student.hbm.xml"/>
        <mapping resource="com/iotek/basic/association/one2one/pojo/Passport_PK.hbm.xml"/>
        <mapping resource="com/iotek/basic/association/one2one/pojo/Person_PK.hbm.xml"/>
        
    </session-factory>
</hibernate-configuration>

注意基于主键的关系映射和基于外键的关系映射之间，映射文件写法上的差异。