hibernate 映射实例 学生 课程 成绩
2013-12-18 14:32
351 查看
学生和课程是多对多,一个学生的一个课程只能对应一个成绩。
所以学生和课程多对多,其中间表多了一个成绩字段。
可以这样设计:
学生和课程通过中间表--成绩,多对多映射。
手动建中间表语句:
create table score(id int primary key auto_increment,student_id int refrences student(id),course_id int references course(id),score int);
package com.bjsxt.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
@Entity
public class Course {
private int id;
private String name;
@Id
@GeneratedValue
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;
}
}
package com.bjsxt.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="score")
public class Score {
private int id;
private int score;
private Student student;
private Course course;
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
@ManyToOne
@JoinColumn(name="student_id")
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
@ManyToOne
@JoinColumn(name="course_id")
public Course getCourse() {
return course;
}
public void setCourse(Course course) {
this.course = course;
}
}
package com.bjsxt.hibernate;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
@Entity
public class Student {
private int id;
private String name;
private Set<Course> courses = new HashSet<Course>();
@ManyToMany
@JoinTable(name="score",
joinColumns=@JoinColumn(name="student_id", referencedColumnName="id"),
inverseJoinColumns=@JoinColumn(name="course_id", referencedColumnName="id")
)
public Set<Course> getCourses() {
return courses;
}
public void setCourses(Set<Course> courses) {
this.courses = courses;
}
@Id
@GeneratedValue
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;
}
}
测试类
package com.bjsxt.hibernate;
import java.util.Map;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
public class HibernateTreeTest {
private static SessionFactory sessionFactory;
@BeforeClass
public static void beforeClass() {
//new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
@AfterClass
public static void afterClass() {
sessionFactory.close();
}
@Test
public void testSave() {
Student s = new Student();
s.setName("zhangsan");
Course c = new Course();
c.setName("java");
Score score = new Score();
score.setCourse(c);
score.setStudent(s);
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(s);
session.save(c);
session.save(score);
session.getTransaction().commit();
session.close();
}
@Test
public void testLoad() {
testSave();
Session session = sessionFactory.openSession();
session.beginTransaction();
Student s = (Student)session.load(Student.class, 1);
for(Course c : s.getCourses()) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
}
public static void main(String[] args) {
beforeClass();
}
}
所以学生和课程多对多,其中间表多了一个成绩字段。
可以这样设计:
学生和课程通过中间表--成绩,多对多映射。
手动建中间表语句:
create table score(id int primary key auto_increment,student_id int refrences student(id),course_id int references course(id),score int);
package com.bjsxt.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
@Entity
public class Course {
private int id;
private String name;
@Id
@GeneratedValue
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;
}
}
package com.bjsxt.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="score")
public class Score {
private int id;
private int score;
private Student student;
private Course course;
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
@ManyToOne
@JoinColumn(name="student_id")
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
@ManyToOne
@JoinColumn(name="course_id")
public Course getCourse() {
return course;
}
public void setCourse(Course course) {
this.course = course;
}
}
package com.bjsxt.hibernate;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
@Entity
public class Student {
private int id;
private String name;
private Set<Course> courses = new HashSet<Course>();
@ManyToMany
@JoinTable(name="score",
joinColumns=@JoinColumn(name="student_id", referencedColumnName="id"),
inverseJoinColumns=@JoinColumn(name="course_id", referencedColumnName="id")
)
public Set<Course> getCourses() {
return courses;
}
public void setCourses(Set<Course> courses) {
this.courses = courses;
}
@Id
@GeneratedValue
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;
}
}
测试类
package com.bjsxt.hibernate;
import java.util.Map;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
public class HibernateTreeTest {
private static SessionFactory sessionFactory;
@BeforeClass
public static void beforeClass() {
//new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
@AfterClass
public static void afterClass() {
sessionFactory.close();
}
@Test
public void testSave() {
Student s = new Student();
s.setName("zhangsan");
Course c = new Course();
c.setName("java");
Score score = new Score();
score.setCourse(c);
score.setStudent(s);
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(s);
session.save(c);
session.save(score);
session.getTransaction().commit();
session.close();
}
@Test
public void testLoad() {
testSave();
Session session = sessionFactory.openSession();
session.beginTransaction();
Student s = (Student)session.load(Student.class, 1);
for(Course c : s.getCourses()) {
System.out.println(c.getName());
}
session.getTransaction().commit();
session.close();
}
@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
}
public static void main(String[] args) {
beforeClass();
}
}
相关文章推荐
- Hibernate第十三讲 学生课程分数映射
- 求解???使用hibernate配置一个定义好的数据库。学生-课程-成绩
- Hibernate学习笔记_关系映射_学生_课程_分数
- 第32天(就业班) hibernate框架概述、ORM概念、hibernate第一个实例、api讲解、查询方式、主配置文件、映射配置、主键映射
- 查处每门功课前两名学生的名字,课程名,成绩
- hibernate映射一对多双向关联关系实例
- 例 9.7 有n个结构体变量,内含学生学号、姓名和3门课程的成绩。要求输出平均成绩最高的学生的信息(包括学号、姓名、3门课程成绩和平均成绩)。
- 学生各门课程成绩统计SQL语句大全
- 习题 9.5 有10个学生,每个学生的数据包括学号、姓名、3门课程的成绩,从键盘输入10个学生数据,要求输出3门课程总平均成绩,以及最高分的学生的数据(包括学号、姓名、3门课程成绩、平均分数)。
- Hibernate.isInitialized方法的使用(表是使用多对多映射关系实例中的表):
- 【C语言经典实例】-数组-使用数组统计学生成绩
- Hibernate实例--注解配置表映射
- 常用的学生、课程、成绩、教师表的查询
- Hibernate(四)一对多映射 补充二:单向多对一关系(学生->班级)
- Hibernate关联关系映射实例速查
- hibernate课程 初探单表映射3-2 基本类型
- 学生成绩管理系统(课程设计)
- hibernate课程 初探一对多映射2-4 Mysql创建数据库表
- Hibernate实体关系映射(OneToMany单边)——完整实例
- 学生成绩管理网站之——课程视频分享实现