I have a parent object with a child collection containing one element, the child collection contains a "grandchild" collection containing 3 elements.
I am loading the parent object from the database using NHibernate as follows
Parent parentObject = session.Query<Parent>()
.FetchMany(x => x.Children)
.ThenFetchMany(x => x.GrandChildren)
.Where(x => x.Id = "someparentid")
.Single();
What I'm finding is that there are duplicate children objects (3 in total) attached to the parent object when there should be only one. (There are 3 grandchild objects correctly attached to each child.) Eager loading the children collection only works correctly.
Do you know how I can achieve loading of the full parent object without duplicate children?
Best Answer
If you map Children and GrandChildren as set, you can avoid the cartesian product. You need to define Children and Grandchildren as collections:
And in the mapping (using FluentNHibernate):