Java JPA 只为嵌套实体写入 ID

发布于 2025-01-10 19:12:24 字数 639 浏览 0 评论 0原文

如何避免对数据库进行不必要的查询？我有 LoadEntity 和两个嵌套实体 - CarrierEntity 和 DriverEntity。 Java类：

@Entity
public class LoadEntity {
  ...
  
  @ManyToOne
  @JoinColumn(name="carrier_id", nullable=false)
  private CarrierEntity carrierEntity;

  @ManyToOne
  @JoinColumn(name="driver_id", nullable=false)
  private DriverEntity driverEntity;
}

但是API向我发送了rierId和driverId。我做到了：

DriverEntity driverEntity = driverService.getDriverEntityById(request.getDriverId());
loadEntity.setDriverEntity(driverEntity);
loadRepository.save(loadEntity);

如何用JPA只写driverId？

原文

How can I avoid unnecessary queries to the DB?
I have LoadEntity with two nested entity - CarrierEntity and DriverEntity. Java class:

@Entity
public class LoadEntity {
  ...
  
  @ManyToOne
  @JoinColumn(name="carrier_id", nullable=false)
  private CarrierEntity carrierEntity;

  @ManyToOne
  @JoinColumn(name="driver_id", nullable=false)
  private DriverEntity driverEntity;
}

But API send me carrierId and driverId. I make it:

DriverEntity driverEntity = driverService.getDriverEntityById(request.getDriverId());
loadEntity.setDriverEntity(driverEntity);
loadRepository.save(loadEntity);

How can I write only driverId with JPA?

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未蓝澄海的烟 2025-01-17 19:12:24

借助 Spring Data JPA，您始终可以依靠纯 SQL。
当然，这将回避 JPA 为您提供的所有伟大/烦人的逻辑。
这意味着您不会收到任何事件，并且内存中的实体可能与数据库不同步。
因此，如果您使用乐观锁定，您还可以增加版本列。

也就是说，您可以像这样更新一个字段：

interface LoadRepository extends CrudRepository<LoadEntity, Long> {

    @Query(query="update load_entity set driver_id = :driverId where carrier_id=:carrier_id", nativeQuery=true)
    @Modifying
    void updateDriverId(Long carrierId, Long driverId);

}

如果您只是想避免加载 DriverEntity，您也可以使用 JpaRepository.getById

With Spring Data JPA you can always fall back on plain SQL.
Of course, this will side step all the great/annoying logic JPA gives you.
This means you won't get any events and the entities in memory might be out of sync with the database.
For this reason you might also increase the version column, if you are using optimistic locking.

That said you could update a sing field like this:

interface LoadRepository extends CrudRepository<LoadEntity, Long> {

    @Query(query="update load_entity set driver_id = :driverId where carrier_id=:carrier_id", nativeQuery=true)
    @Modifying
    void updateDriverId(Long carrierId, Long driverId);

}

If you just want to avoid the loading of the DriverEntity you may also use JpaRepository.getById

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