JPA Parent Child relationship on same entity(view)

Question

I have a view which has a parent-child relationship. So I have my entity this way:

@Entity
@Table(name = "assessment_v", schema = "hlt_hrsc")
public class HrscLabellingAssessmentVEntity {

@Id
private String id;

@Column(name = "child_id")
private String childId;

@ManyToOne(cascade = {CascadeType.ALL})
@JoinColumn(name = "id")
private HrscLabellingAssessmentVEntity parent;

@OneToMany(mappedBy = "parent")
private Set<HrscLabellingAssessmentVEntity> child = new HashSet<>();
}

when I start my application it throws an error : nested exception is org.hibernate.MappingException: Could not determine type for: java.util.Set

Please find the below image of the view for parent child eg:

id          child_id
120.35871   120.35872
120.35872   null

Here 120.35872 is the parent record and 120.35871 is the child record. The parentId is maintained on the child_id column. My requirement is when I try to fetch the parent it should have the child records also.

what am I doing wrong??

Answer 1

Please check this example

    @Entity
    @Table(name = "assessment_v", schema = "hlt_hrsc")
    public class HrscLabellingAssessmentVEntity {
    
    @Id
    private String id;
    
    @Column(name = "child_id")
    private String childId;
     
    @JsonBackReference
    @JoinColumn(name = "parent_id", referencedColumnName = "id")
    @ManyToOne(fetch = FetchType.LAZY)
    @Fetch(FetchMode.JOIN)
    private HrscLabellingAssessmentVEntity parentId;

     @JsonManagedReference
     @OneToMany(mappedBy = "parentId", cascade = CascadeType.ALL)
     private Set<HrscLabellingAssessmentVEntity> child = new HashSet<>();
    }