hibernate 映射关系

1. 基本多对一关系映射

             一个班级对应多个学生

             

package cn.liubingxu.bean;import java.util.List;public class Student {private int sid;private String username;//private List <Grade> grade;private Grade grade;public Student() {super();}}

  

package cn.liubingxu.bean;public class Grade {private int gid;private String gradename;public Grade() {super();}}

<class name="cn.liubingxu.bean.Grade" table="grade"><meta attribute="class-description">一方班级</meta><id name="gid" type="int" column="gid"><generator class="native" /></id><property name="gradename" column="gradename" type="string"/></class><class name="cn.liubingxu.bean.Student" table="student"><meta attribute="class-description">多方学生</meta><id name="sid" type="int" column="sid"><generator class="native" /></id><property name="username" column="username" type="string"/><many-to-one name="grade" column="gid"  class="cn.liubingxu.bean.Grade" cascade="none">   </many-to-one></class>

           学生表中添加班级id字段

             

         2.