hibernate对象关系映射的配置

一对一主键关联单双向

<?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 package="com.wepull.pojo">
    <class name="IdCard" table="t_idcard">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- 双向配置如下 -->
        <one-to-one name="p"></one-to-one>
    </class>
</hibernate-mapping>

<hibernate-mapping package="com.wepull.pojo">
    <class name="Person" table="t_person">
        <id name="id">
            <generator class="foreign">
                <param name="property">i</param>
            </generator>        
        </id>
        <property name="name"></property>
        <!-- person找Idcard  单向 -->
        <one-to-one name="i" constrained="true"></one-to-one>
    </class>
</hibernate-mapping>

一对一外键关联单双向

<?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 package="com.wepull.pojo">
    <class name="IdCard" table="t_idcard">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- 双向配置    级联删除-->
        <one-to-one name="p" property-ref="i" cascade="delete"></one-to-one>
    </class>
</hibernate-mapping>



<hibernate-mapping package="com.wepull.pojo">
    <class name="Person" table="t_person">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- person找Idcard  单向 -->
        <many-to-one name="i" unique="true"></many-to-one>
    </class>
</hibernate-mapping>

一对多/多对一

<?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 package="com.wepull.pojo">
    <class name="Student" table="t_student">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- 多对一配置如下 -->
        <many-to-one name="c" class="Classes"></many-to-one>
    </class>
</hibernate-mapping>

<hibernate-mapping package="com.wepull.pojo">
    <class name="Classes" table="t_classes">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- 一对多 -->
        <set name="s" inverse="true"><!-- 由学生管理 -->
        <!-- column:多的一方持有一的一方的外键字段 -->
            <key column="c"></key>
            <one-to-many class="Student" />
        </set>
    </class>
</hibernate-mapping>

多对多单双向

<hibernate-mapping package="com.wepull.pojo">
    <class name="Role" table="t_role">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- 多对多 -->
        <set name="u" table="t_user_role">
            <key column="r"></key>
            <many-to-many class="User" column="u"></many-to-many>
        </set>    
    </class>
</hibernate-mapping>


<hibernate-mapping package="com.wepull.pojo">
    <class name="User" table="t_user">
        <id name="id">
            <generator class="native"></generator>        
        </id>
        <property name="name"></property>
        <!-- 多对多配置如下 -->
        <set name="r" table="t_user_role">
            <key column="u"></key>
            <many-to-many class="Role" column="r"></many-to-many>
        </set>
        
    </class>
</hibernate-mapping>

Annotation注解(多对一)

import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
/**
 * @author fcs
 * 不能自动删除表
 * 多对一单向     多方持有一方的外键
 * 2014-8-24
 */

@Entity
public class Student {
    private int id;
    private String name;
    private Classes c;
    
    @ManyToOne(fetch=FetchType.LAZY)//延迟加载
    @JoinColumn(name="cid")//修改表字段名  防止自动生成sid
    public Classes getC() {
        return c;
    }
    public void setC(Classes c) {
        this.c = c;
    }
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)//主键自增长
    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;
    }
}