【hibernate框架】关系映射之一对一单向外键关联(XML实现)

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在XML里面如何单向关联：

学生证与学生卡是一对一的关系，在学生证那一方做关联

Student.java:

package cn.edu.hpu.model;public class Student {private int id;private String name;private int age;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}

StudentIdCard.java:

package cn.edu.hpu.model;public class StuIDCard {private int id;private String num;private Student student;//与学生实体类单向关联public int getId() {return id;}public void setId(int id) {this.id = id;}public String getNum() {return num;}public void setNum(String num) {this.num = num;}public Student getStudent() {return student;}public void setStudent(Student student) {this.student = student;}}

StudentIdCard.hbm.xml:

<?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>    <class name="cn.edu.hpu.model.StuIDCard">        <id name="id">            <generator class="native"></generator>        </id>        <property name="num"/>        <!-- 站在当前类的立场考虑，设外键关联的时候设置的 many-to-one-->        <!-- many-to-one多个学生证对应一个学生 unique="true"唯一为true，必须保证id唯一，就变成了一对一-->        <!--column定义哪个字段做为外键关联类字段-->        <many-to-one name="student" column="id" unique="true"></many-to-one>    </class></hibernate-mapping>

Student.hbm.xml:

<?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.edu.hpu.model">    <class name="Student" table="student" dynamic-update="true"><id name="id" column="id"><generator class="native"></generator>  </id>          <property name="name"></property>        <property name="age"></property>    </class></hibernate-mapping>

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