I need to query on a property of a subclass. Here are the entities involved:
@Entity
@Data
public class Course {
@Id
private Long id;
@ManyToOne
@JoinColumn(name = "personId")
private Person person;
}
@Entity
@Data
@Inheritance(strategy = InheritanceType.JOINED)
public class Person {
@Id
private Long id;
private String name;
}
@Entity
@Data
@EqualsAndHashCode(callSuper=true)
public class Student extends Person {
@ManyToOne
@JoinColumn(name="studentTypeId")
private StudentType studentType;
}
@Entity
@Data
public class StudentType {
@Id
private Long id;
@Convert(converter = StudentTypeConverter.class)
private StudentTypeEnum name;
@RequiredArgsConstructor
@Getter
@ToString
public static enum StudentTypeEnum {
GRADUATE("Graduate");
private final String name;
}
}
I'm trying to query using a Spring Data repository:
public interface CourseRepository extends Repository<Course> {
List<Course> findByCoursePersonStudentTypeName(@Param("studentTypeName") String studentTypeName);
}
This doesn't work though. It generates an error stating No property StudentTypeName found for Person!. This makes sense since the property exists only on Student.
How can I write this method (preferably) or use JPQL to find the courses by type of student?
How about this:
@Query("select c from Course c join c.person as p where UPPER(p.studentType.name) = UPPER(?1)")
List<Course> findByCoursePersonStudentTypeName(String studentTypeName);
This uses a feature of Hibernate called implict casting.