How to use methods on @ManyToOne connection within JpaRepository?

Question

Hibernate

There are two entities:

@Entity
@Table(name = "AUTHORS", schema = "NEWS_SCHEMA")
@Getter
@Setter
@NoArgsConstructor
public class Author {

    @Id
    @Column(name = "ID")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @Column(name = "NAME")
    private String name;

    @Column(name = "SURNAME")
    private String surname;

    @Column(name = "DATE_OF_BIRTH")
    private Date dob;

    @OneToMany(cascade = {CascadeType.DETACH,CascadeType.MERGE,CascadeType.PERSIST,CascadeType.REFRESH},
            mappedBy = "authorOfArticle")
    private List<Article> articlesOfAuthor;

    public void addArticleToAuthor(Article article) {

        if (articlesOfAuthor == null) {
            articlesOfAuthor = new ArrayList<>();
        }
        articlesOfAuthor.add(article);

        article.setAuthorOfArticle(this);
    }


    public Author(String name, String surname, Date dob) {
        this.name = name;
        this.surname = surname;
        this.dob = dob;
    }
}

@Entity
@Table(name = "ARTICLES",schema = "NEWS_SCHEMA")
@Getter @Setter
@NoArgsConstructor
public class Article {

    @Id
    @Column(name = "ID")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @Column(name = "TITLE")
    private String title;

    @Column(name = "CONTENT")
    private byte[] content;

    @Column(name = "CATEGORY_ID")
    int categoryId;

    
    @ManyToMany(cascade = {CascadeType.DETACH,CascadeType.MERGE,CascadeType.PERSIST,CascadeType.REFRESH})
    @JoinTable(
            name = "ARTICLES_CATEGORIES",
            schema = "NEWS_SCHEMA",
            joinColumns = @JoinColumn(name = "ARTICLE_ID"),
            inverseJoinColumns = @JoinColumn(name = "CATEGORY_ID"))

    private List<Category> categoriesInArticle;

    @ManyToOne(cascade = {CascadeType.DETACH,CascadeType.MERGE,CascadeType.PERSIST,CascadeType.REFRESH})
    @JoinColumn(name = "AUTHOR_ID" )
    private Author authorOfArticle;

    public Article( String title, int categoryId, Author author) {
        this.title = title;
        this.categoryId = categoryId;
        this.authorOfArticle = author;
    }
}

To perform CRUD operations, I use JpaRepository, but I don't understand how I should call the
addArticleToAuthor method if Jpa does everything for me, I can't fit it into a transaction, such as when working with a session. Thanks in advance for any clarifications.

Answer 1

You just need to call method void addArticleToAuthor(Article article)
A at the end call method author.save()
Here is a useful article on ManyToOne & OneToMany
https://thorben-janssen.com/best-practices-many-on...
https://www.baeldung.com/hibernate- one-to-many