Jpa many-to-one unidirectional delete-CodePudding

Let's say we have many-to-one relationship where PostComment contains parent entity Post. There is no cascading here. My goal is to clean PostComments and I wonder, whether exists the way better than setting PostComment.post = null, persisting entity and then delete PostComment? I use Spring data over JPA\Hibernate, so, JPQL queries and Native queries are welcome.

CodePudding user response：

Can't you try something like this?

em.createQuery("delete from PostComment pc where pc.post = :post") .setParameter("post", postId) .executeUpdate();

CodePudding user response：

Assuming your entity Post and PostComments are managed by hibernate. Clearing the list should make hibernate realize that the comments are removed. You may need to add "orphanRemoval = true" in the @OneToMany annotation in your Post Class.

public class Post {
....
@OneToMany(orphanRemoval = true)
private List<PostComment> postComments;
....
}

Your Service with removeMethod:

@Transactional
public void clearComments() {
    Optional<Post> post = postRepository.findById(1);
    post.get().getPostComments.clear();
}