与复合主键的 OneToOne JPA 关系答案

【问题标题】：OneToOne JPA relation with composite primary key与复合主键的 OneToOne JPA 关系
【发布时间】：2019-11-25 14:15:09
【问题描述】：

我有这个不工作的双向 OneToOne 示例：

@Embeddable
public class SolicitudGUCDetalleId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", precision = 10, scale = 0, insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCDET")
public class SolicitudGUCDetalle implements Serializable {

  @EmbeddedId
  private SolicitudGUCDetalleId id;

  @OneToOne(fetch = FetchType.LAZY, mappedBy = "solicitudGUCDetalle")
  private SolicitudGUCEnvio solicitudGUCEnvio;

  ...
}

@Embeddable
public class SolicitudGUCEnvioId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCENV")
public class SolicitudGUCEnvio implements Serializable {


  @EmbeddedId
  private SolicitudGUCEnvioId id;

  @OneToOne(fetch = FetchType.LAZY)
  @PrimaryKeyJoinColumns({
      @PrimaryKeyJoinColumn(name = "IDLINEA", referencedColumnName = "IDLINEA"),
      @PrimaryKeyJoinColumn(name = "IDPEDIDO", referencedColumnName = "IDPEDIDO")})
  private SolicitudGUCDetalle solicitudGUCDetalle;

  ...
}

我已阅读有关该问题的信息，并且我有两种可行的方法来实现这种关系。

1 - 对复合主键使用相同的类：

@Embeddable
public class SolicitudGUCId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", precision = 10, scale = 0, insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCDET")
public class SolicitudGUCDetalle implements Serializable {

  @EmbeddedId
  private SolicitudGUCId id;

  @OneToOne(fetch = FetchType.LAZY, mappedBy = "solicitudGUCDetalle")
  private SolicitudGUCEnvio solicitudGUCEnvio;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCENV")
public class SolicitudGUCEnvio implements Serializable {

  @EmbeddedId
  private SolicitudGUCId id;

  @OneToOne(fetch = FetchType.LAZY)
  @PrimaryKeyJoinColumns({
      @PrimaryKeyJoinColumn(name = "IDLINEA", referencedColumnName = "IDLINEA"),
      @PrimaryKeyJoinColumn(name = "IDPEDIDO", referencedColumnName = "IDPEDIDO")})
  private SolicitudGUCDetalle solicitudGUCDetalle;

  ...
}

2 - 切换到 @OneToMany 关系并将相关实体存储在 Set 中：

@Embeddable
public class SolicitudGUCDetalleId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", precision = 10, scale = 0, insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCDET")
public class SolicitudGUCDetalle implements Serializable {

  @EmbeddedId
  private SolicitudGUCDetalleId id;

  @OneToMany(fetch = FetchType.LAZY, mappedBy = "solicitudGUCDetalle")
  private Set<SolicitudGUCEnvio> solicitudes;

  ...
}

@Embeddable
public class SolicitudGUCEnvioId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCENV")
public class SolicitudGUCEnvio implements Serializable {

  @EmbeddedId
  private SolicitudGUCEnvioId id;

  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumns({
      @JoinColumn(name = "IDLINEA", referencedColumnName = "IDLINEA",
          nullable = false, insertable = false, updatable = false),
      @JoinColumn(name = "IDPEDIDO", referencedColumnName = "IDPEDIDO",
          nullable = false, insertable = false, updatable = false)})
  private SolicitudGUCDetalle solicitudGUCDetalle;

  ...
}

我想知道我是否可以按照我的第一个示例实现这种关系。如果答案是否定的，我想知道为什么。

【问题讨论】：

标签： java jpa

【解决方案1】：

这似乎是一个“派生的身份”；因此您可以尝试对选项 1 稍作改动：

@Embeddable
public class SolicitudGUCId implements Serializable {

    @Column(name = "IDPEDIDO", insertable = false, updatable = false)
    @Size(max = 36)
    private String idPedido;

    @Column(name = "IDLINEA", precision = 10, scale = 0, insertable = false, updatable = false)
    private long idLinea;

    ...
}

@Entity
@Table(name = "TRIISOLIDGUCDET")
public class SolicitudGUCDetalle implements Serializable {

    @EmbeddedId
    private SolicitudGUCId id;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "solicitudGUCDetalle")
    private SolicitudGUCEnvio solicitudGUCEnvio;

    ...
}

@Entity
@Table(name = "TRIISOLIDGUCENV")
public class SolicitudGUCEnvio implements Serializable {

    @EmbeddedId
    private SolicitudGUCId id;

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumns({
        @JoinColumn(name = "IDLINEA", referencedColumnName = "IDLINEA"),
        @JoinColumn(name = "IDPEDIDO", referencedColumnName = "IDPEDIDO")})
    @MapsId
    private SolicitudGUCDetalle solicitudGUCDetalle;

    ...
}

请注意，SolicitudGUCEnvio.solicitudGUCDetalle 使用 @MapsId 和 @JoinColumns 进行注释（而不是 @PrimaryKeyJoinColumns）。

在第 2.4.1 节的JPA 2.2 spec 中讨论了派生的身份（带有示例）。

【讨论】：

对不起，但在我的评论中我说这个例子是有效的。我正在尝试纠正第一个示例，它有两个不同的 EmbeddedId。谢谢。
@jvano 啊，我的错。您可以使用第一个示例，可能没有任何问题。但是 JPA 规范建议您将其调整为类似于我的回复中的代码：“请注意，在此示例中使用 PrimaryKeyJoinColumn 而不是 MapsId 将导致相同的映射。对于派生身份的映射，首选使用 MapsId。” [页。 38]

【解决方案2】：

这是我正在寻找的解决方案：

@Embeddable
public class SolicitudGUCDetalleId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", precision = 10, scale = 0, insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCDET")
public class SolicitudGUCDetalle implements Serializable {

  @EmbeddedId
  private SolicitudGUCDetalleId id;

  @OneToOne(fetch = FetchType.LAZY, mappedBy = "solicitudGUCDetalle")
  private SolicitudGUCEnvio solicitudGUCEnvio;

  ...
}

@Embeddable
public class SolicitudGUCEnvioId implements Serializable {

  @Column(name = "IDPEDIDO", insertable = false, updatable = false)
  @Size(max = 36)
  private String idPedido;

  @Column(name = "IDLINEA", insertable = false, updatable = false)
  private long idLinea;

  ...
}

@Entity
@Table(name = "TRIISOLIDGUCENV")
public class SolicitudGUCEnvio implements Serializable {


  @EmbeddedId
  private SolicitudGUCEnvioId id;

  @OneToOne(fetch = FetchType.LAZY)
  @JoinColumns({@JoinColumn(name = "IDLINEA", referencedColumnName = "IDLINEA"),
      @JoinColumn(name = "IDPEDIDO", referencedColumnName = "IDPEDIDO")})
  @MapsId
  private SolicitudGUCDetalle solicitudGUCDetalle;

  ...
}

@Brian Vosburgh，感谢您的帮助

【讨论】：