HQL / Nested Eager Loading
I am wondering what the best way is to load nested values for lazy loaded objects. I'm providing an example to help explain this better.
public class A{
private B b; //Lazy loaded
private C c; //Lazy loaded
private D d; //Lazy loaded
}
public class B{
private E e; //Lazy loaded
private F f; //Lazy loaded
}
public class C{
}
public class D{
}
As an example I want to do:
System.out.println(a.getB().getE());
If I ran the开发者_Python百科 above statement I'd get a lazy load exception.
I can always do the following:
for (A a : somePossiblyLargeList) {
org.hibernate.Hibernate.initialize(a.getB().getE());
}
but obviously performance would suck.
Is there a way I can write a custom HQL query which returns A objects that are pre-populated with those specific nested fields?
Thanks!
Of course.
Use join fetch
in your HQL query, as explained in the Hibernate reference documentation (that you should read):
select a from A a left join fetch a.b b left join fetch b.e e where ...
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