Question

我正在尝试使用JPA Criteria API编写Query。我有以下课程：

Class Booking {

  @ForeignKey(name = "BVisit_ID_FK")
  private List<BVisit> BVisits = new LinkedList<>();

    //other properties
    ...
}

Class Visit{

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "ID")
  private Long id;

}

Class VisitSpecial extends Visit{

  @Column(name = "ARRIVAL_TIME", nullable = false)
  private Date arrivalTime;

  @Column(name = "DEPARTURE_TIME", nullable = false)
  private Date departureTime;

  //other properties...
}`

如何使用JPA Criteria Api（和元模型）编写查询，找到所有预订访问日期值（参数），介于最短到达时间，预订访问的最长出发时间。我使用org.springframework.data.jpa.domain.Specification

查询应如下所示：

SELECT Booking 
from Booking B, Visit V, VisitSpecial VS
where Visit.bookingId = Booking.id and Visit.id = VisitSpecial.id
      and VisitSpecial.arrivalTime = (SELECT MIN(VisitSpecial.arrivalTime) from VisitSpecial VS1 WHERE V.id = VS1.id)
      and VisitSpecial.arrivalTime <= :date
      and VisitSpecial.departureTime = (SELECT MAX(VisitSpecial.departureTime) from VisitSpecial VS1 Where V.id = VS1.id)
      and VisitSpecial.departureTime >= :date

Answer 1

有关通过JPA标准InheritanceType.JOINED处理Subquery和其他继承策略的信息，请参见我的答案here。

使用treat进行向下转换可能有效，但我不建议将其用于复杂查询，因为它可能会产生效率低下的查询（冗余连接），或者完全无法基于您的JPA提供程序（Hibernate，Eclipselink等）运行。

具有Join和继承的JPA Criteria API查询

1 个答案: