如何使一对一的无向映射休眠

我有以下数据库模式：

从图中可以看出，Card_balance指的是Cards。我需要 Cards 实体在切换到 ORM 时有一个 Card_balance 字段，并且有一个单向关系，其中 Cards 指的是 Card_balance。我试着这样做：

  @Entity
@Table(name = "CARDS")
public class Cards implements Serializable {

    @Id
    @Column(name = "CARD_ID")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CARDS_SEQ")
    @SequenceGenerator(name = "CARDS_SEQ", sequenceName = "CARDS_SEQ")
    private Long cardId;

    ...

    @OneToOne
    @JoinColumn(name="CARD_ID", nullable = false)
    private CardBalance cardBalance;

并将 cardId 字段添加到 card_balance

 @Entity
@Table(name = "CARD_BALANCE")
public class CardBalance {

    @Id
    @Column(name = "BALANCE_ID")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CARD_BALANCE_SEQ")
    @SequenceGenerator(name = "CARD_BALANCE_SEQ", sequenceName = "CARD_BALANCE_SEQ")
    private Long balanceId;

    ...

    @Column(name="CARD_ID")
    private Long cardId;

但是这种方法不起作用，因为从卡片数据库中提取时，我得到以下信息：

请告诉我哪里错了。