Gentlemen, I'm trying to model a rather unusual relationship, and AFAIK there's no way to achieve that in Hibernate, but wanted to here others thoughts before I give up.

At the guts, the model is plain vanilla. Parent entity A that contains a collection of entity B. Both entities are very simple, PK, and numeric value.

class A {
String id,
int value
List<B> children
}

class B {
String id,
A parent;
int value;
}

What's interesting about this relationship is that certain instances of A can contain very large number of Bs (in thousands). That turns out to be a performance hit when operating on those instances. What's interesting about this case - A doesn't actually care about individual children - but only about the aggregate sum of 'value' field on all children.

Is there a way to map B to A so that it's loaded in a single aggregate SQL operation, as opposed to individual rows. Obviously, I can always create a VIEW on top of table B, but I'd prefer a software approach.

Some options:
1. using a "formula" field on your parent mapping
2. map a separate object to a db view (won't be persistent, but would be loadable)

@Formula worked beautifully. Until now, I didn't realize that I could use subselect within a formula.