| The size() HQL/JPQL expression does not work anymore with nested path. Given the following entities:
(TL;DR: a student can have a teacher (N - 1) a teacher can have multiple skills (N - N))
@Entity
public class Student {
private Integer id;
private Teacher teacher;
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@ManyToOne(optional = false)
@JoinColumn(name = "teacher_id")
public Teacher getTeacher() {
return teacher;
}
public void setTeacher(Teacher teacher) {
this.teacher = teacher;
}
}
@Entity
public class Teacher {
private Integer id;
private Set<Student> students = new HashSet<>();
private Set<Skill> skills = new HashSet<>();
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@OneToMany(mappedBy = "teacher", cascade = CascadeType.ALL, orphanRemoval = true)
public Set<Student> getStudents() {
return students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
@ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
public Set<Skill> getSkills() {
return skills;
}
public void setSkills(Set<Skill> skills) {
this.skills = skills;
}
}
@Entity
public class Skill {
private Integer id;
private Set<Teacher> teachers;
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@ManyToMany(mappedBy = "skills")
public Set<Teacher> getTeachers() {
return teachers;
}
public void setTeachers(Set<Teacher> teachers) {
this.teachers = teachers;
}
}
I expect the following query:
select student from Student student where size(student.teacher.skills) > 0
To translate into:
select
student0_.id as id1_1_,
student0_.teacher_id as teacher_2_1_
from
Student student0_ cross
join
Teacher teacher1_
where
student0_.teacher_id=teacher1_.id
and (
select
count(skills2_.teachers_id)
from
Teacher_Skill skills2_
where
teacher1_.id=skills2_.teachers_id
)>0
(this is the query generated by version 5.4.12) While it translates into:
select
student0_.id as id1_1_,
student0_.teacher_id as teacher_2_1_
from
Student student0_
where
(
select
count(skills1_.teachers_id)
from
Teacher_Skill skills1_
where
student0_.id = skills1_.teachers_id
)>0
(since version 5.4.13 the where condition is not the good one anymore) The subquery is comparing student.id (instead of teacher_id) against teachers_id. I think this is related to work done in  HHH-13619 Closed (introduction of CollectionSizeNode) |
