liverrrr 2017-05-29 03:40 采纳率: 0%
浏览 957
已结题

hibernate一对一,一对多更新语句问题

object references an unsaved transient instance - save the transient instance before flushing: com.SelectCourseSystem.pojo.Student
三个类,一个StudentUser,一个Student,一个StudentCourse,其中StudentUser与Student是一对一关系(单向),Student与StudentCourse是一对多关系(单向关联表)现在执行跟新语句出现上面的问题
@Entity
@Table(name="t_studentuser")
public class StudentUser {
private int id;
private String username;
private String password;
private Student student;
......
@OneToOne(cascade=CascadeType.ALL)
@JoinColumn(name="studentId")
public Student getStudent() {
return student;
}
...
}
@Entity
@Table(name="t_student")
public class Student {
private int id;
private String name;
private int age;
private String sex;
private String specialty;
private List courses;
....
@OneToMany(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
@JoinTable(
name="CourseForStudent",
joinColumns = @JoinColumn( name="studentid"),
inverseJoinColumns = @JoinColumn( name="studentcourseid")
)
public List getCourses() {
return courses;
}
....
}
测试类
public void testUpdateStudentUser() {
Configuration configuration = new AnnotationConfiguration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = null;
Transaction transaction = null;
Query query=null;
int i=0;
try {
session = sessionFactory.openSession();
transaction=session.beginTransaction();
String hql="update StudentUser as s set s.username=?,s.password=?,s.student=? where s.id =?";
query=session.createQuery(hql);
List courses=new ArrayList();
StudentCourse course01=new StudentCourse("math", "xsyuBbuilding", "xiaoming");
StudentCourse course02=new StudentCourse("physical", "xsyuBbuilding", "lihua");
StudentCourse course03=new StudentCourse("biological", "xsyuBbuilding", "xiaohua");
courses.add(course01);
courses.add(course02);
courses.add(course03);
Student student=new Student("zhouhouyu", 21, "man", "physical", courses);
query.setString(0, "201401020133");
query.setString(1, "020133");
query.setParameter(2, student);
query.setInteger(3, 1);
i=query.executeUpdate();
transaction.commit();
} catch (Exception e) {
e.printStackTrace();
transaction.rollback();
} finally {
session.close();
System.out.println(i);
}
}
小白求教

  • 写回答

1条回答 默认 最新

  • 搬运工木木 2017-05-31 05:56
    关注

    Student student=new Student("zhouhouyu", 21, "man", "physical", courses);
    如果这个是新添加的记录,先要调用save保存,如果是已经存在的,不应该new,而是应该查询出来

    评论

报告相同问题?

悬赏问题

  • ¥15 逻辑谓词和消解原理的运用
  • ¥15 请求分析基于spring boot+vue的前后端分离的项目
  • ¥15 三菱伺服电机按启动按钮有使能但不动作
  • ¥15 js,页面2返回页面1时定位进入的设备
  • ¥200 关于#c++#的问题,请各位专家解答!网站的邀请码
  • ¥50 导入文件到网吧的电脑并且在重启之后不会被恢复
  • ¥15 (希望可以解决问题)ma和mb文件无法正常打开,打开后是空白,但是有正常内存占用,但可以在打开Maya应用程序后打开场景ma和mb格式。
  • ¥20 ML307A在使用AT命令连接EMQX平台的MQTT时被拒绝
  • ¥20 腾讯企业邮箱邮件可以恢复么
  • ¥15 有人知道怎么将自己的迁移策略布到edgecloudsim上使用吗?