Question

我正在使用带有hibernate的spring jpa存储库来保存我的oracle数据库的entites。如何使用Spring-Hibernate获取我的oracle数据库序列的下一个值？

这是我的活动课程：

@Entity
public class Event {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  private Long seriesId;

  private String description;

  public Event() {
  }

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public Long getSeriesId() {
    return seriesId;
  }

  public void setSeriesId(Long seriesId) {
    this.seriesId = seriesId;
  }

  public String getDescription() {
    return description;
  }

  public void setDescription(String description) {
    this.description = description;
  }
}

我需要为事件解析器中的所有事件系列获取序列的下一个值。

public class EventResolver {

    @Autowired
    private EventRepository eventRepository;

    public void createSeriesOfEvents(List<EventAPI> eventsToCreate){

        Long seriesId = null; // TODO: Get the series id from database sequence

        for (EventAPI currEvent : eventsToCreate){
            Event newEvent = new Event();
            newEvent.setDescription(currEvent.description);
            newEvent.setSeriesId(seriesId);
            eventRepository.save(newEvent);
        }

    }
}

感谢您提供任何帮助..

Answer 1

最后我以Spring的方式解决了我的问题，你只需要在JpaRepository中添加一个本机查询，如下所示：

public interface EventRepository extends JpaRepository<Event, Long> {

 @Query(value = "SELECT seq_name.nextval FROM dual", nativeQuery = 
        true)
 Long getNextSeriesId();

Answer 2

您可以在JPA中使用此方法：

Query q = em.createNativeQuery("select seq_name.nextval from dual");
return (Long)q.getSingleResult();

Answer 3

像这样注释你的id属性：

@Id
@GeneratedValue(generator = "idSequence")
@SequenceGenerator(schema = "MYORASCHEMA", name = "idSequence", sequenceName = "MY_ORACLE_SEQ_NAME", allocationSize = 1)
@Column(name="ID")
private Long id;

Answer 4

在Spring 5中，您可以使用其内置类之一来完成此任务，例如OracleSequenceMaxValueIncrementer

查看此软件包中的所有可用选项：https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/jdbc/support/incrementer/package-summary.html

使用spring hibernate从序列中获取Next值

4 个答案: