Java：集合映射中的重复列

Question

我正在尝试使用 LinkedHashMap 为我的主要实体 B 创建一个 OneToMany 映射，其中包含实体 VC 和 P，但我收到以下错误：

集合映射中的重复列： com.test.model.B.pricing 列：b_name

我可能是错的，但我相信它与@JoinColumns 或@MapKeyJoinColumn 注释有关，因为我以前没有做过这样的事情，所以我很确定我做这部分不正确.

我的目标是我应该能够提供三个字段：

b_name pc 和 c_id 例如VC/VCId

为了得到a 和d_a 例如P.

另外，如果有更好的方法来构建事物，那么我会全神贯注，因为我个人不太喜欢我设置表格的方式（如果我能有 b 和b_p 表，其中b_p 可以只包含来自p 映射的所有五个字段（键和值）。

这是我的主要实体

@Setter
@Getter
@Entity
@Table(name = "b")
public class B implements Serializable {

  @Id
  @Column(nullable = false)
  private String name;

  @OneToMany(cascade = CascadeType.PERSIST)
  @JoinTable(
          name = "b_p",
          joinColumns = @JoinColumn(name = "b_name", referencedColumnName = "name"))
  @MapKeyJoinColumns({
          @MapKeyJoinColumn(name = "b_name"),
          @MapKeyJoinColumn(name = "p_c"),
          @MapKeyJoinColumn(name = "c_id")
  })
  private Map<VC, Price> pricing = new LinkedHashMap<>();

  ...
}

地图的钥匙

@Setter
@Getter
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "v_c")
public class VC implements Serializable {

  @EmbeddedId private VCId vcId;
}

密钥的 PK/复合密钥

@Setter
@Getter
@NoArgsConstructor
@AllArgsConstructor
@Embeddable
public class VCId implements Serializable {

  @Column(name = "b_name")
  private String bName;

  @Column(name = "p_c")
  private SomeEnum pc;

  @Column(name = "c_id")
  private String cId;
}

地图的价值

@Setter
@Getter
@NoArgsConstructor
@Embeddable
@Entity
@Table(name = "price")
public class Price implements Serializable {

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

  @Column(name = "amount")
  private BigDecimal amount;

  @Column(name = "discount_amount")
  private BigDecimal discountAmount;
}

数据库表

CREATE TABLE b
(
    name                    VARCHAR(100) NOT NULL PRIMARY KEY
    ...
);

CREATE TABLE v_c
(
    bundle_name         VARCHAR(100) NOT NULL,
    physical_currency   TEXT         NOT NULL,
    coin_id             VARCHAR(50)  NOT NULL,

    FOREIGN KEY (b_name) REFERENCES b (name) ON DELETE CASCADE,
    PRIMARY KEY (b_name, p_c, c_id)
);

CREATE TABLE p
(
    id                  BIGSERIAL    NOT NULL PRIMARY KEY,
    amount              NUMERIC,
    discount_amount     NUMERIC      DEFAULT 0.00
);

CREATE TABLE b_p
(
    bname         VARCHAR(100) NOT NULL,
    p_c   TEXT    NOT NULL,
    c_id          VARCHAR(50)  NOT NULL,
    price_id      BIGSERIAL    NOT NULL,

    FOREIGN KEY (b_name, p_c, c_id) REFERENCES v_c (b_name, p_c, c_id) ON DELETE CASCADE,
    FOREIGN KEY (price_id) REFERENCES price (id) ON DELETE CASCADE,
    PRIMARY KEY (b_name, p_c, c_id)
);

Answer 1

为防止重复映射错误，您只需指定哪个连接应该更新列，如下所示：

@OneToMany(cascade = CascadeType.PERSIST)
@JoinTable(name = "bundle_pricing",
  joinColumns = @JoinColumn(name = "bundle_name",
    referencedColumnName = "name"))
@MapKeyJoinColumns({
  @MapKeyJoinColumn(name = "bundle_name", insertable = false, updatable = false),
  @MapKeyJoinColumn(name = "physical_currency"), @MapKeyJoinColumn(name = "coin_id")})
private Map<VirtualCurrency, Price> pricing = new LinkedHashMap<>();

注意 insertable = false, updatable = false 用于 MapKeyJoinColumn 中的 bundle_name

Answer 2

从 MapKeyJoinColumns 中删除 @MapKeyJoinColumn(name = "bundle_name")，因为当我们在 JoinTable 中创建 JoinColumn 时，它将创建我们不需要再次提及的列。

@JoinTable(
          name = "bundle_pricing",
          joinColumns = @JoinColumn(name = "bundle_name", referencedColumnName = "name"))
  @MapKeyJoinColumns({
          @MapKeyJoinColumn(name = "physical_currency"),
          @MapKeyJoinColumn(name = "coin_id")
  })