Hibernate多对多关联失败，关系不存在

我正在做一个涂鸦式的项目。在这里，我有三个班级，三张桌子，分别是教授、活动、学生。 每个教授可以有多个事件，事件与学生有多对多的关系。教授身上所有的积垢操作都很正常。使用事件，我可以添加/删除事件，但更新失败。当我试图创建一个学生时，同样的错误也会发生。我正在粘贴域代码

活动：

@Entity
@Table(name = "events")
public class Events {
    @Id
    @Column(name="eventid")
    private int eventid;

     @ManyToMany()
   @JoinColumn(name = "studentid")
    private Set<Students> students2 = new HashSet<Students>();

    public Set<Students> getStudents2() {
        return students2;
    }

    public void setStudents2(Set<Students> students2) {
        this.students2 = students2;
    }

    public int getEventid() {
        return eventid;
    }

    public void setEventid(int eventid) {
        this.eventid = eventid;
    }
}

学生主题：

@Transactional
@Repository
public class  StudentsDAOImpl implements StudentsDAO{

 @Override
public void addStudent(Students students, int eventid) {

    if (session == null) {
        session = this.sessionFactory.openSession();

    } else {
        session = this.sessionFactory.getCurrentSession();
    }
    Events events = (Events) session.get(Events.class, eventid);
    System.out.println("Canvas id here is" + eventid);

    events.getStudents2().add(students);
    students.setEvents2(events);
    session.merge(students);
    session.flush();
}

}

编辑事件时的堆栈跟踪：

org.postgresql.util.PSQLException: ERROR: relation "events_students" does not exist
  Position: 573
    org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2198)
    org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1927)
    org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255)
    org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:561)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:419)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:304)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:82)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:449)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:202)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:137)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)

StackTrace在添加学生时：

org.postgresql.util.PSQLException: ERROR: relation "events_students" does not exist
  Position: 573
    org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2198)
    org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1927)
    org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255)
    org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:561)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:419)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:304)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:82)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:449)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:202)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:137)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    org.hibernate.loader.collection.plan.AbstractLoadPlanBasedCollectionInitializer.initialize(AbstractLoadPlanBasedCollectionInitializer.java:100)
    org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:693)
    org.hibernate.event.internal.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:92)

---

您需要创建一个偶数学生表来实际实现许多映射。@Zeus好的，我不知道。非常感谢。

org.postgresql.util.PSQLException: ERROR: relation "events_students" does not exist
  Position: 573
    org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2198)
    org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1927)
    org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255)
    org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:561)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:419)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:304)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:82)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:449)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:202)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:137)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)

org.postgresql.util.PSQLException: ERROR: relation "events_students" does not exist
  Position: 573
    org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2198)
    org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1927)
    org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255)
    org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:561)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:419)
    org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:304)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:82)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:449)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:202)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:137)
    org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    org.hibernate.loader.collection.plan.AbstractLoadPlanBasedCollectionInitializer.initialize(AbstractLoadPlanBasedCollectionInitializer.java:100)
    org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:693)
    org.hibernate.event.internal.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:92)