NHibernate one-to-many relationship without bidirectional association

Question

Is my understanding correct, that the following class and table design is not possible in NHibernate:

public class Parent
{
   public virtual Guid Id { get; set; }
   public virtual ISet<Child> Children { get; set; }
   ...
}

public class Child
{
   public virtual Guid Id { get; set; }
   ...
}

table Parent { Id, ... }
table Child { Id, ParentId (not null), ... }

So notice the following:

• a one-to-many association between parent and child
• using an ISet
• no bidirectional association from Child back to Parent
• Child's ParentId column is not null

Answer 1

The situation you describe is very much intended by and supported by NHibernate.

Answer 2

My knee jerk reaction was to say that that it was supported but I think you are right. Your options are either - bidirectional relationship or nullable ParentId column in Child table.

Here's a interesting thread where Ayende gets into it in the bug tracker for NH http://nhjira.koah.net/browse/NH-1050 (it's the previous release of NH but I think the answer is the same)