Self OneToMany relation with jointable uknown column error

Question

I have these BaseNews and News entity:

@MappedSuperclass
public class BaseNews extends Model {
    public static Model.Finder<Long, News> find = new Model.Finder<Long, News>(News.class);

    public static News getNewsById(Long newsId) {
        return find.byId(newsId);
    }

    public static List<News> getNewsList(int pageIndex, int pageSize) {
        return find.where()
                   .findPagedList(pageIndex, pageSize)
                   .getList();
    }
 }


    @Entity
    @Table(name = "news")
    public class News extends BaseNews implements Serializable {

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


//    @ManyToOne
//    private News baseNews;


        @OneToMany(cascade = CascadeType.ALL)//,mappedBy = "baseNews")
        @JoinTable(name = "news_similar",
                   joinColumns = {@JoinColumn(name = "base_news_id")},
                   inverseJoinColumns = {@JoinColumn(name = "similar_news_id")}
        )
        private List<News> similarNews;

       //getters, setters...
    }

In both uni and bidirectional case

select t0.id c0, t0.base_news_id c1 from news t0

gives error Unknown column base_news_id

Am I doing it wrong way?

Should I create new Entity NewsSimilar instead of using jointable?

Actually I am reversing existing table.

create table news_similar
(
    id int auto_increment primary key,
    base_news_id int not null,
    similar_news_id int not null,
    constraint news_similar_ibfk_1  foreign key (base_news_id) references news (id) on update cascade on delete cascade,
    constraint news_similar_ibfk_2  foreign key (similar_news_id) references news (id) on update cascade on delete cascade
)

Edit: news_id was completely unrelated problem from other field, anyway solved it.

Your join table annotation isn't being picked up, and your two 'queries' show that it is using either a default OneToMany and so expects a FK field to exist, or in the bidirectional case, you've setup a ManyToOne relationship that also defaults to using a foreign key. What exactly are you doing and what are you after? — Chris, Aug 15 '17 at 14:51
Take a look here. https://stackoverflow.com/questions/3393515/jpa-how-to-have-one-to-many-relation-of-the-same-entity-type — shalama, Aug 15 '17 at 14:52
@Chris updated the question. I am trying to model existing db. — Hursant Bur, Aug 17 '17 at 18:22

Hursant Bur · Accepted Answer · 2017-08-19T09:20:33.890

It turns out that I have ManyToMany relation so, the solution is like this

@Entity
@Table(name = "news")
public class News extends BaseNews implements Serializable {

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


    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "news_similar",
               joinColumns = {@JoinColumn(name = "base_news_id")},
               inverseJoinColumns = {@JoinColumn(name = "similar_news_id")}
    )
    private List<News> similarNews;

   //getters, setters...
}

Came by this solution while reading this article:

https://www.thoughts-on-java.org/ultimate-guide-association-mappings-jpa-hibernate/

Self OneToMany relation with jointable uknown column error

1 Answers1