Hibernate單向@OneToMany關聯觸發外鍵更新

我有以下物體：

@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "TYPE")
public class Type implements Serializable {

  private static final long serialVersionUID = 563398089758359222L;

  @NotNull
  @Column(name = "OBJECT_TYPE")
  private String objectType;

  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TypeNameId")
  @SequenceGenerator(name = "TypeNameId", sequenceName = "SQ_TNAME_WL", allocationSize = 1)
  private Long id;

  @NotNull
  @ToString.Include
  private String code;

  @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
  @JoinColumn(name = "BOUND_TO_ID", referencedColumnName = "ID")
  @JoinColumn(name = "BOUND_TO_CLASS", referencedColumnName = "OBJECT_TYPE")
  private Set<Translation> translations;

}


@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "TRANSLATION")
public class Translation implements Serializable {

  private static final long serialVersionUID = -4974947078465122824L;

  @NotNull
  @Column(name = "OBJECT_TYPE")
  private String objectType;

  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TranslationId")
  @SequenceGenerator(name = "TranslationId", sequenceName = "SQ_LTRANSLATION_WL", allocationSize = 1)
  private Long id;

  @Size(max = 4000)
  @Column(name = "VALUE")
  private String value;

  @Size(max = 150)
  @Column(name = "LOCALE")
  private String locale;


  @Size(max = 150)
  @Column(name = "BOUND_TO_CLASS")
  private String boundToClass;

  @Column(name = "BOUND_TO_ID")
  private Long boundToId;

}

其他物體也可能在 Translations 表中有他們的翻譯，但不包括與 Translation 物體相關的映射。在創建帶有翻譯的型別時，Hibernate 想要執行以下 SQL：

Hibernate：插入型別（code，object_type，id）值（“code”，“Type”，1）

Hibernate：插入翻譯（bound_to_class，bound_to_id，locale，object_type，value，id）值（null，null，“en_US”，“Translation”，“American code”，2）

在 bound_to_id、bound_to_class 和 locale 列上有一個不可延遲的唯一約束。由于在 Hibernate SQL 中 bound_to_class 和 bound_to_id 為空，因此無法在同一語言環境中為不同型別創建翻譯。

How do I change the mappings to allow translation creations without making the unique constraint deferrable or using bidirectional association?

uj5u.com熱心網友回復：

除了建立雙向關系：

public class Type {
  ..
  @OneToMany(mappedBy="type", fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
  private Set<Translation> translations;
}
..
public class Translation {
  ..
  @ManyToOne
  @JoinColumn(name = "BOUND_TO_ID", referencedColumnName = "ID")
  @JoinColumn(name = "BOUND_TO_CLASS", referencedColumnName = "OBJECT_TYPE")
  Type type;
}

然后將為您設定 fk 值，另一種方法是自己在 Translation 中映射 BOUND_TO_ID 和 BOUND_TO_CLASS，然后自己從任何 Type 實體中提取它們：

public class Translation {
  ..
  @Column(name = "BOUND_TO_CLASS")
  private String objectType;

  @Column(name = "BOUND_TO_ID")
  private Long objectId;

}

然后，您需要將 Type 中的關系標記為只讀：

public class Type {
  ..
  @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
  @JoinColumn(name = "BOUND_TO_ID", referencedColumnName = "ID", updatable=false, insertable=false)
  @JoinColumn(name = "BOUND_TO_CLASS", referencedColumnName = "OBJECT_TYPE", updatable=false, insertable=false)
  private Set<Translation> translations;
}

由于生成了 Type id，您需要先在 Type 上呼叫 persist，重繪 背景關系以確保分配了 ID，然后使用 ID 和 objectType 設定您希望創建的任何 Transaction 實體以指向它。

標籤：hibernate jpa one-to-many

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