I have a scenario where I have to get the list of all masters who have no students (set is empty) and also students whose status is cancelled
@Entity
@Table(name="Masters")
public class Master {
@Id
private String id;
@One To Many mapping here
private Set<Student> students = new HashSet<>();
}
@Entity
@Table(name="Students")
public class Student {
@Id
private String id;
@Column(name = "Status")
private String status;
}
I have my code as
final CriteriaBuilder cb = getEM().getCriteriaBuilder();
final CriteriaQuery<Tuple> criteriaQuery = cb.createTupleQuery();
final Root<Master> mvRoot = criteriaQuery.from(Master.class);
Predicate predicate = cb.conjunction();
this gives me list of masters who dont have any students
predicate = cb.and(predicate, cb.isEmpty(mvRoot.join(Master.STUDENTS)));
This is giving the list of masters with student status cancelled
final Join<Master, Set<Student>> studentJoin = mvRoot.join(Master.STUDENTS);
predicate = cb.and(predicate, cb.equal(studentJoin.get(Student.status), "Cancelled"));
I am not able to fetch both at a time, and if I club both i am just getting masters with students status cancelled and not the masters with no students
Can some one please advise me.