CODEWITHSUNDEEP
javahibernatejpaormmany-to-many
Vjeetje
Vjeetje

Reputation: 5384

delete everything in a many-to-many relationship (JPA)

I have the following model (reduced):

@Entity
public class Video {
    @ManyToMany(fetch=FetchType.EAGER, cascade=CascadeType.ALL)
    @JoinTable(name = "video_tag", joinColumns = {
            @JoinColumn(name = "video_id", referencedColumnName = "id") }, inverseJoinColumns = {
                    @JoinColumn(name = "tag_id", referencedColumnName = "id") })
    private Set<Tag> tags;
}

@Entity
public class Tag {
    @ManyToMany(mappedBy="tags", fetch=FetchType.LAZY)
    private Set<Video> videos;
}

I have a database where videos are connected to multiple tags and vice versa. I want to delete all videos and cascade it to delete all tags as well. Calling remove on a Video entity results in a cycle and after a few round of going back and forth between a tag and a video, the java compiler prints a stack dump of the cycle.

How can I remove a video / all videos using JPA, preferably by removing all videos and cascading the remove to the tags.

Upvotes: 1

Views: 1092

Answers (1)

Daniel Rch.
Daniel Rch.

Reputation: 170

The actions are:

  1. Breakdown relationships (object schema)
  2. Update owner entity (video in this case)

  3. Remove videos entities also remove tag entities because cascade anotation in Video Class.

    //Remove relationships
List<Video> videoList;
for (Video v : videoList) {
    for(Tag t : video.getTags()){
        t.getVideos.remove(v);
        v.getTags.remove(t);
    }
}

//Update owner entities
for (Video v : videoList) {
    Session sess = HibernateUtil.getSessionFactory().openSession();
    Transaction tx = sess.beginTransaction();
    sess.update(v);
    tx.commit();
    sess.close();
}

//Remove owner entities
for (Video v : videoList) {
    Session sess = HibernateUtil.getSessionFactory().openSession();
    Transaction tx = sess.beginTransaction();
    sess.delete(v);
    tx.commit();
    sess.close();
}

Upvotes: 1

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