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
1 <hibernate-mapping package="entity"> 2 <class name="Course"> 3 <id name="id"> 4 <generator class="native"/> 5 </id> 6 <property name="name"/> 7 <set name="scores" inverse="true"> 8 <key column="courseId"/> 9 <one-to-many class="Score"/> 10 </set> 11 </class> 12 </hibernate-mapping>
1 <hibernate-mapping package="entity"> 2 <class name="Score"> 3 <id name="id"> 4 <generator class="native"/> 5 </id> 6 <property name="score"/> 7 <many-to-one name="student" column="studentId" not-null="true"/> 8 <many-to-one name="course" column="courseId" not-null="true" lazy="false"/> 9 </class> 10 </hibernate-mapping>
1 <hibernate-mapping package="entity"> 2 <class name="Student"> 3 <id name="id"> 4 <generator class="native"/> 5 </id> 6 <property name="name"/> 7 8 <set name="scores" inverse="true" lazy="false"> 9 <key column="studentId"/> 10 <one-to-many class="Score"/> 11 </set> 12 </class> 13 </hibernate-mapping>
方式二配置（只有两个文件）
1 <hibernate-mapping package="entity"> 2 <class name="Student"> 3 <id name="id"> 4 <generator class="native"/> 5 </id> 6 <property name="name"/> 7 <set name="scores" lazy="true" table="Score"> 8 <key column="studentId"/> 9 <!-- 组成元素映射 --> 10 <composite-element class="Score"> 11 <!-- Score类中引用当前实体类的属性名 --> 12 <parent name="student"/> 13 <property name="score"/> 14 <!-- Score类与Course类的多对一关联 --> 15 <many-to-one name="course" class="Course" column="courseId"/> 16 </composite-element> 17 </set> 18 </class> 19 </hibernate-mapping>
1 <hibernate-mapping package="entity"> 2 <class name="Course"> 3 <id name="id"> 4 <generator class="native"/> 5 </id> 6 <property name="name"/> 7 <set name="scores" lazy="true" table="Score" inverse="true"> 8 <key column="courseId"/> 9 <composite-element class="Score"> 10 <parent name="course"/> 11 <property name="score"/> 12 <many-to-one name="student" class="Student" column="studentId" foreign-key="studentId"/> 13 </composite-element> 14 </set> 15 </class> 16 </hibernate-mapping>
