Fetch.Join() not working in Fluent NHibernate

Question

I have the following mapping override on one side of the relationship:

public void Override(AutoMapping<ItemAsmtDetailDh> mapping)
{
    mapping.HasMany<WAsmtDetail>(x => x.WAsmtDetails).Inverse().AsBag().Cascade.AllDeleteOrphan().Access.PascalCaseField(Prefix.Underscore).Not.LazyLoad().Fetch.Join();
}

and on the other side of the relationship I have:

public void Override(AutoMapping<WAsmtDetail> mapping)
{
    mapping.References<ItemAsmtDetailDh>(x => x.ItemAsmtDetailDh).Not.Nullable().Not.LazyLoad().Fetch.Join();
}

When I use the ShowSql option I see that it's still issuing separate select statements for the WAsmtDetails giving me the dreaded "n + 1 selects" problem. Why is ".Not.LazyLoad().Fetch.Join()" being ignored?

Note: I'm using Fluent NHibernate version 1.1, not version 2.1, because of a bug in the newer version. (See my answer for this question for bug details.) I'm using NHibernate version 2.1.2.4000.

Answer 1

You are most likely loading the data in a way that isn't affected by Fetch.Join() in the mapping (like HQL or Linq). From the NHibernate documentation:

The fetch strategy defined in the mapping document affects:

• retrieval via Get() or Load()
• retrieval that happens implicitly when an association is navigated
• ICriteria queries
• HQL queries if subselect fetching is used