hibernate映射(学生-科目-成绩)

实体类

1 public class Student {
2     private int id;
3     private String name;
4     private Set<Score> scores = new HashSet<Score>();   //一对多
5 }

1 public class Score {
2     private int id;
3     private Student student;  //1对1
4     private Course course;      //1对1
5     private Double score;
6 }

1 public class Course {
2     private int id;
3     private String name;
4     private Set<Score> scores = new HashSet<Score>();    //一对多
5 }

方式一映射关系（多对一）有3个配置文件

 <hibernate-mapping package="entity">
     <class name="Course">
         <id name="id">
             <generator class="native"/>
         </id>
         <property name="name"/>
         <set name="scores" inverse="true">
             <key column="courseId"/>
             <one-to-many class="Score"/>
         </set>
     </class>
 </hibernate-mapping>

 <hibernate-mapping package="entity">
     <class name="Score">
         <id name="id">
             <generator class="native"/>
         </id>
         <property name="score"/>
         <many-to-one name="student" column="studentId" not-null="true"/>
         <many-to-one name="course" column="courseId" not-null="true" lazy="false"/>
     </class>
 </hibernate-mapping>

 <hibernate-mapping package="entity">
     <class name="Student">
         <id name="id">
             <generator class="native"/>
         </id>
         <property name="name"/>

         <set name="scores" inverse="true" lazy="false">
             <key column="studentId"/>
             <one-to-many class="Score"/>
         </set>
     </class>
 </hibernate-mapping>

方式二配置（只有两个文件）

 <hibernate-mapping package="entity">
     <class name="Student">
         <id name="id">
             <generator class="native"/>
         </id>
         <property name="name"/>
         <set name="scores" lazy="true" table="Score">
             <key column="studentId"/>
             <!-- 组成元素映射 -->
             <composite-element class="Score">
                 <!-- Score类中引用当前实体类的属性名 -->
                 <parent name="student"/>
                 <property name="score"/>
                 <!-- Score类与Course类的多对一关联 -->
                 <many-to-one name="course" class="Course" column="courseId"/>
             </composite-element>
         </set>
     </class>
 </hibernate-mapping>

 <hibernate-mapping package="entity">
     <class name="Course">
         <id name="id">
             <generator class="native"/>
         </id>
         <property name="name"/>
         <set name="scores" lazy="true" table="Score" inverse="true">
             <key column="courseId"/>
             <composite-element class="Score">
                 <parent name="course"/>
                 <property name="score"/>
                 <many-to-one name="student" class="Student" column="studentId" foreign-key="studentId"/>
             </composite-element>
         </set>
     </class>
 </hibernate-mapping>