JPA:insert后的数据表不显示@joincolumn@manytone

Question

我正在尝试一个使用JPA和JSF-primeface的网络项目。我有一个错误，插入/更新一个具有@ManyToOne关系的对象。

插入后，@JoinColumn为空字段。（抱歉，我无法发布图片，这里是图片链接）

插入后

然后，在重新加载列表后，空白字段恢复正常

重新加载后

我使用单向@ManyToOne实体

位置JAVA

@Entity
@Table(name = "place")
@XmlRootElement

public class Place implements Serializable {
   private static final long serialVersionUID = 1L;
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   @Basic(optional = false)
   @Column(name = "id")
   private Integer id;
   ...
   @Basic(optional = false)
   @NotNull
   @Column(name = "prefecture_id")
   private int prefectureId;

   @ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
   @JoinColumn(name = "prefecture_id",referencedColumnName = "id", updatable = false,insertable = false)
   private Aken prefecture;

阿肯。JAVA

@Entity
@Table(name = "aken")
@XmlRootElement
public class Aken implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @NotNull
    @Column(name = "id")
    private Short id;
    @Size(max = 50)
    @Column(name = "data")
    private String data;

方法更新到数据库

@Stateless
@TransactionManagement(TransactionManagementType.BEAN)
public class PlaceFacade extends AbstractFacade<Place> {
    @PersistenceContext(unitName = "JutenPU")
    private EntityManager em;

    @Resource
    private UserTransaction userTransaction;

    public void edit(Place place){
      try{
          getUserTransaction().begin();
          getEntityManager().merge(place);
          getUserTransaction().commit();
          }catch(Exception e){
            System.out.println(e.getMessage());
          }
      }

方法检索表上的数据

public List<Place> findAll() {
    javax.persistence.criteria.CriteriaQuery cq =   getEntityManager().getCriteriaBuilder().createQuery();
    cq.select(cq.from(Place.class));
    return getEntityManager().createQuery(cq).getResultList();
}

我使用的是JavaEE7、glassfish服务器4和primefaces 4.0

多谢你的帮忙

Answer 1

@JoinColumn(name = "prefecture_id",referencedColumnName = "id", updatable = false,insertable = false)

您已将“放置外键”列标记为只读。

删除限制：@JoinColumn（name=“perfessional_id”，referencedColumnName=“id”）