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>