兩個實體@ManyToOne應該加入同一個表

Question

我有以下實體

學生

@Entity 
public class Student implements Serializable { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private Long id; 

    //getter and setter for id 

} 

教師

@Entity 
public class Teacher implements Serializable { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private Long id; 

    //getter and setter for id 

} 

任務

@Entity 
public class Task implements Serializable { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private Long id; 

    @ManyToOne(optional = false) 
    @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "student_id") }) 
    private Student author; 

    @ManyToOne(optional = false) 
    @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "teacher_id") }) 
    private Teacher curator; 

    //getters and setters 

} 

考慮到author和curator已經存儲在數據庫中，並且都處於附加狀態。我想堅持我Task：

Task task = new Task(); 
task.setAuthor(author); 
task.setCurator(curator); 
entityManager.persist(task); 

的Hibernate執行的SQL語句：

insert 
    into 
    student_task 
    (teacher_id, id) 
    values 
    (?, ?) 

其中，當然，導致null value in column "student_id" violates not-null constraint

誰能解釋這個問題，可能的方式來解決它？

UPDATE

見下面我自己的解決方案。

Answer 1

我已經解決了我的問題與@SecondaryTable的幫助和@JoinTable切換到@JoinColumn ：

任務

@Entity 
@SecondaryTable(name="student_task") 
public class Task implements Serializable { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private Long id; 

    @ManyToOne(optional = false) 
    @JoinColumn(table = "student_task", name = "student_id") 
    private Student author; 

    @ManyToOne(optional = false) 
    @JoinColumn(table = "student_task", name = "teacher_id") 
    private Teacher curator; 

    //getters and setters 

} 

現在，生成的SQL是這樣的：

insert 
    into 
    student_task 
    (student_id, teacher_id, id) 
    values 
    (?, ?, ?) 

，一切工作就好:)

Answer 2

我認爲你缺少的JoinColumns標籤...

joinColumns = { @JoinColumn(name = "student_id", referencedColumnName = "id") } 

joinColumns = { @JoinColumn(name = "teacher_id", referencedColumnName = "id") } 

在作者和策展人分別

還記得，那inversjoincolumn處於被佔用表中的列..所以它必須是是這樣的：

inverseJoinColumns = {@JoinColumn(name="id")})