java - 具有复合主键的 OneToOne JPA 关系

Question

我有这个双向 OneToOne 示例不起作用:

@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;

  ...
}

我已经了解了这个问题，并且我有两种可能的方法来实现这种有效的关系。

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第一个示例来实现这种关系。如果答案是否定的，我想知道为什么。

Answer 1

这似乎是“派生身份”；因此，您可以尝试对选项 1 稍作修改:

@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(与 @PrimaryKeyJoinColumns 相反) )。

JPA 2.2 spec 中讨论了派生身份(并附有示例)在第 2.4.1 节中。