Question

我想制作一张桌子，让我们说桌子的名字是Car。它将包含3列，brandId，typeId和sizeId。我希望所有列都是主键。 typeId和sizeId是来自不同表格的列。我已经尝试创建代码，但如果我为每列使用注释@Id，则会出现错误＆＃34;找不到超类型＆＃34;。

代码如下。

@Entity
@Table(name = "CAR")
public class Car implements Serializable {
  private static final long serialVersionUID = -1576946068763487642L;

  @Id
  @Column(name = "BRAND_ID", nullable = false, length = 20)
  private String brandId;

  @Id
  @ManyToOne
  @JoinColumn(name = "TYPE_ID", nullable = false)
  private TypeId typeId;

  @Id
  @ManyToOne
  @JoinColumn(name = "SIZE_ID", nullable = false)
  private SizeId sizeId;



  public String getBrandId() {
      return brandId;
  }

  public void setBrandId(String brandId) {
      this.brandId= brandId;
  }


  public TypeId getTypeId() {
      return typeId;
  }

  public void setTypeId (TypeId typeId) {
      this.typeId= typeId;
  }


  public SizeId getSizeId() {
      return sizeId;
  }

  public void setSizeId (SizeId sizeId) {
      this.sizeId= sizeId;
  }

}

所以，我正在使用Google搜索并发现我可以使用@EmbeddedId来创建复合主键。实体的代码是这样的：

@Entity
@Table(name = "CAR")
public class Car implements Serializable {
  private static final long serialVersionUID = -1576946068763487642L;

  @EmbeddedId
  private CarPk carPk;


  public CarPk getCarPk () {
      return carPk ;
  }

  public void setCarPk (CarPk carPk ) {
      this.carPk = carPk ;
  }

}

和Embeddable类：

@Embeddable
public class CarPk implements Serializable {
  private static final long serialVersionUID = -83738833L;


  @Column(name = "BRAND_ID", nullable = false, length = 20)
  private String brandId;


  @ManyToOne
  @JoinColumn(name = "TYPE_ID", nullable = false)
  private TypeId typeId;


  @ManyToOne
  @JoinColumn(name = "SIZE_ID", nullable = false)
  private SizeId sizeId;

  public String getBrandId() {
      return brandId;
  }

  public void setBrandId(String brandId) {
      this.brandId= brandId;
  }


  public TypeId getTypeId() {
      return typeId;
  }

  public void setTypeId (TypeId typeId) {
      this.typeId= typeId;
  }


  public SizeId getSizeId() {
      return sizeId;
  }

  public void setSizeId (SizeId sizeId) {
      this.sizeId= sizeId;
  }
}

然后，我想基于brandId创建可以找到列的界面。接口代码：

public interface CardDao extends PagingAndSortingRepository<Car, Long>, QueryDslPredicateExecutor<Car> {
     public Car findByBrandId(String brandId);
}

不幸的是，代码是错误的：

＆＃34;无法根据路径＆＃34;解析属性[brandId]。

所以我在Entity类中为brandId创建了setter getter：``

@Entity
@Table(name = "CAR")
public class Car implements Serializable {
  private static final long serialVersionUID = -1576946068763487642L;

  @EmbeddedId
  private CarPk carPk;


  public CarPk getCarPk () {
      return carPk ;
  }

  public void setCarPk (CarPk carPk ) {
      this.carPk = carPk ;
  }

  public brandId getBrandId (){
      return carPk.getBrandId();
  }

  public void setBrandId (String brandId){
      this.carPk.setBrandId(brandId);
  }
}

错误未显示，但表格的车辆数据也不会出现。

我的问题是：

接口代码是否为真？我想知道在brandId类中，当brandId的列在Embeddable时，brandId是否可以找到它。
实体类中array[0] = [1, 2, 3, 4] array[1] = [2, 3, 4, 5] array[2] = [3, 4, 6, 10, 15, 20] array[3] = [15, 20, 25]的setter getter是真的吗？

谢谢！

Answer 1

您有一个复合主键。请参阅Compound Primary Keys。

复合主键错误

1 个答案: