Hibernate JPA Entity how to save @Entity which have @OnetoMany @Entity inside that @Entity another @OnetoMany

Question

For Example

@Entity
class Person{

    @OneToMany
    private List<Wife> wife;

}

@Entity
class Wife{

    @OneToMany
    private List<Child> child;

}

@Entity
class Child{

    private String name;


}

how to save this at once in jpa hibernate

Answer 1

You can do something like this

The Person Table will be:

@Entity
@Table(name = "person")
public class Person {

    private Long id;
    List<Wife> wives;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(
            name = "native",
            strategy = "native"
    )
    @Column(name = "pk_id")
    public final Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @OneToMany(mappedBy = "person", cascade = CascadeType.ALL, orphanRemoval = true)
    public List<Wife> getWives() {
        return wives;
    }

    public void setWives(List<Wife> wives) {
        this.wives = wives;
    }
}

and Wife Table:

@Entity
@Table(name = "wife")
public class Wife {
    private Long id;
    private List<Child> children;
    private Person person;


    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(
            name = "native",
            strategy = "native"
    )
    @Column(name = "pk_id")
    public final Long getId() {
        return id;
    }



    @OneToMany(mappedBy = "mother", cascade = CascadeType.ALL, orphanRemoval = true)
    public List<Child> getChildren() {
        return children;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "fk_person_id", nullable = false, foreignKey = @ForeignKey(name = "fk_person_wife"))
    public Person getPerson() {
        return person;
    }
    public void setId(Long id) {
        this.id = id;
    }

    public void setPerson(Person person) {
        this.person = person;
    }

    public void setChildren(List<Child> children) {
        this.children = children;
    }
}

and finally child entity:

@Entity
@Table(name = "child")
public class Child {
    private Long id;
    private Wife mother;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(
            name = "native",
            strategy = "native"
    )
    @Column(name = "pk_id")
    public final Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "fk_wife_id", nullable = false, foreignKey = @ForeignKey(name = "fk_wife_child"))
    public Wife getMother() {
        return mother;
    }

    public void setMother(Wife mother) {
        this.mother = mother;
    }
}

we need to create a repository for "person" entity. with JPA it's easy to do that. like this

public interface PersonRepository extends JpaRepository<Person, Long> { }

after creating repository, we need to use PersonRepository to persist a person object.

Child child = new Child(); 
Wife wife = new Wife(); 
wife.setChildren(List.of(child));
child.setMother(wife); 
Person person = new Person(); 
person.setWives(List.of(wife)); 
wife.setPerson(person); 
personRepository.save(person);