Question

This is my “header” entity:

@Entity
@Table(name = "documenti")
@Inheritance(strategy=InheritanceType.JOINED)
public class Documento implements Serializable {

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

    @OneToMany(
        mappedBy="testataDocumento",
        cascade=CascadeType.ALL,
        fetch=FetchType.LAZY
    )
    private Set<RigaDocumento> righe= new HashSet<RigaDocumento>();

//...
}

and these are the “rows”:

@Entity
@Table(name="righe_documenti")
public class RigaDocumento implements Serializable {

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

    @ManyToOne
    private Documento testataDocumento;

//...
}

Well I have a common situation:

Documento d = new Documento();
// various Documento settings
List<RigaDocumento> rows;
// creation of rows
d.setRighe( rows );

Then I persist d.

Header is persisted correctly and rows too but…

the “testataDocumento_id” field (the key to the “one” side of the relationships) in the rows record is NULL.

Do I have to do a:

row.setTestataDocumento(d);

?

Why??

Answer 1

Yes, you do have to call row.setTestataDocumento(d); as it is the owning side of the relationship. Ideally, you would have an addRow() method in Documento which would add the row to set and also set the document of the row.