hibernate 建表一对一 就是一对多，多的一方外键唯一unique

Person.java

package cn.itcast.hiberate.sh.domain.onetoone;

import java.io.Serializable;
import java.util.Set;

public class Person implements Serializable{
    private Long cid;
    private String cname;
    private String description;
    
    public Long getCid() {
        return cid;
    }

    public void setCid(Long cid) {
        this.cid = cid;
    }

    public String getCname() {
        return cname;
    }

    public void setCname(String cname) {
        this.cname = cname;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
    
    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    private Address address;
}

Person.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="cn.itcast.hiberate.sh.domain.Classes">
        <id name="cid" length="5" type="java.lang.Long">
            <generator class="increment"></generator>
        </id>
        <property name="cname" length="20" type="java.lang.String"></property>
        
        <property name="description" length="100" type="java.lang.String"></property>
        <!-- 
            set元素对应类中的set集合
            通过set元素使classes表与student表建立关联
               key是通过外键的形式让两张表建立关联
               one-to-many是通过类的形式让两个类建立关联
            
            cascade 级联
               save-update
                   1、当 保存班级的时候，对学生进行怎么样的操作
                        如果学生对象在数据库中没有对应的值，这个时候会执行save操作
                        如果学生对象在数据库中有对应的值，这个时候会执行update操作
               delete
               all
            inverse  维护关系
               true      不维护关系     
               false     维护关系
               default   false
         -->
        <set name="students" cascade="save-update" inverse="true">
            <!-- 
                key是用来描述外键
             -->
            <key>
                <column name="cid"></column>
            </key>
            <one-to-many class="cn.itcast.hiberate.sh.domain.Student"/>
        </set>
    </class>
</hibernate-mapping>

Address.java

package cn.itcast.hiberate.sh.domain.onetoone;

import java.io.Serializable;

public class Address implements Serializable{
    private Long sid;
    private String sname;
    
    private Person person;
    

    public Person getPerson() {
        return person;
    }
    public void setPerson(Person person) {
        this.person = person;
    }
    public Long getSid() {
        return sid;
    }
    public void setSid(Long sid) {
        this.sid = sid;
    }
    public String getSname() {
        return sname;
    }
    public void setSname(String sname) {
        this.sname = sname;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    private String description;
}

Address.hbm.xml  外键唯一

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="cn.itcast.hiberate.sh.domain.Student">
        <id name="sid" length="5">
            <generator class="increment"></generator>
        </id>
        <property name="sname" length="20"></property>
        <property name="description" length="100"></property>
        <!-- 
            多对一
              column 外键
         -->
        <many-to-one name="classes" class="cn.itcast.hiberate.sh.domain.Classes" column="cid" cascade="save-update" unique="true"></many-to-one>
    </class>
</hibernate-mapping>