HQL one to many select single object in single query

Question

I want to retrieve such object of class A that has "inside" object C.

I have a class A:

public class A {
...
@OneToMany(mappedBy = "classA")
private List<B> listOfB;

}

class B:

public class B {

...
@ManyToOne
@JoinColumn(name = "A_FK")
private A AObject;

@OneToMany(mappedBy = "classB")
private List<C> ListOfC;

}

and class C:

public class C {
...

private String CId;

@ManyToOne
@JoinColumn(name = "B_FK")
private B BObject;


}

Explanation: I have objects A which have list of objects B (one B object can be in only one object A), every object B has inside few objects C (object C can be in only one B).

How can I retrieve object A using single HQL query, knowing Id of object C?

Answer 1

Try this HQL query:

select a from A as a 
    join a.listOfB as b
    join b.listOfC as c 
    where c.CId = '1234'

Full java example:

Query query = this.session.createQuery("select a from A as a join a.listOfB as b join b.listOfC as c where c.CId = :id");
query.setString("id", "1234"); 
A a = (A)query.uniqueResult();

Answer 2

It turned out that I don't have to use any joins sin hibernate will join tables by it self. Working query for this example:

select Bclass.AObject 
from B as Bclass 
where Bclass.id = (select Cclass.Bclass.id FROM C Cclass WHERE c.Id=:Id)