HQL Join Query with InheritanceType.JOIN 基于子类的条件

Question

使用NamedQuery，如何根据子类的字段提取使用InheritanceType.JOINED的相关表？

我有一个类似的设置：

使用NamedQuery类：

@NamedQuery(<named-query>)
@Entity
@Table(name="T_PERSON")
public class Person {
private Vehicle vehicle;
}

第一个类引用的抽象类：

@Entity
@Table(name = "T_VEHICLE")
@DiscriminatorColumn(name = "vehicleType")
@Inheritance(strategy = InheritanceType.JOINED)
public abstract class Vehicle {
private Long vehicleId;
private String vehicleType;
}

弃权类的具体子类：

@Entity
@Table(name = "T_CAR")
@DiscriminatorValue("CAR")
public class Car extends Vehicle {
private String make;
}

我正试图在Person类中编写一个<named-query>，它将类似于以下SQL:

SELECT * FROM T_PERSON person
LEFT JOIN T_VEHICLE vehicle ON vehicle.VEHICLE_ID = person.VEHICLE_ID
LEFT JOIN T_CAR car on car.VEHICLE_ID = vehicle.VEHICLE_ID
WHERE car.MAKE = 'Honda'

我遇到的问题是，Person类只引用了超类Vehicle，而没有引用子类Car，因此尝试为此编写NamedQuery模拟程序失败：

Select person from Person person 
left join person.Vehicle vehicle
where vehicle.make = 'Honda'

Answer 1

解决方案是这样查询它：

SELECT person FROM Person person 
INNER JOIN person.vehicle vehicle, Car car
WHERE vehicle.vehicleId = car.vehicleId
AND car.make = 'Honda'