一对多关系的JPA/Hibernate映射表

Question

@Entity
@Table(name = "ASSESSMENT")
public class Assessment{

    @OneToMany(fetch = FetchType.EAGER)
    private Set<Comment> auditComments = new HashSet<Comment>();

    @OneToMany(fetch = FetchType.EAGER)
    private Set<Comment> comments = new HashSet<Comment>();
}

@Entity
@Table(name = "COMMENT")
public class Comment{

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

    @Column(columnDefinition = "text")
    private String text;
}

如果在评估中只有一组注释，这将非常好地工作。ASSESSMENT_COMMENT只有两列：

[ASSESSMENT_ID, COMMENT_ID]

它将完美地代表一对多的关系。

现在问题来了：

[ASSESSMENT_ID, COMMENT_ID, AUDITCOMMENT_ID]

那么，1)这是Hibernate中已知的bug吗？2）有办法解决这个问题吗？我可以强制Hibernate创建两个映射表，每个映射表一个吗？请记住，我不能更改comment类来引用assession（业务逻辑需求）

Answer 1

首先，您可以使用注释表中的两列来指向他们的评估：

@OneToMany(fetch = FetchType.EAGER)
@JoinColumn(name = "audit_commented_assessment_id")
private Set<Comment> auditComments = new HashSet<Comment>();

@OneToMany(fetch = FetchType.EAGER)
@JoinColumn(name = "commented_assessment_id")
private Set<Comment> comments = new HashSet<Comment>();

如果您想要两个联接表，只需这样说：

@OneToMany(fetch = FetchType.EAGER)
@JoinTable(name = "assessment_audit_comment",
           joinColumns = @JoinColumn(name = "assessment_id"),
           inverseJoinColumns = @JoinColumn(name = "comment_id"))
private Set<Comment> auditComments = new HashSet<Comment>();

@OneToMany(fetch = FetchType.EAGER)
@JoinTable(name = "assessment_comment",
           joinColumns = @JoinColumn(name = "assessment_id"),
           inverseJoinColumns = @JoinColumn(name = "comment_id"))
private Set<Comment> comments = new HashSet<Comment>();

当然，这在文档中有解释。