NHibernate SetFetchMode doesn't work with nested criteria

Question

Assuming I run the following code:

var placementCriteria = DetachedCriteria.For<ResidentialPlacementClientService>();
placementCriteria.Add(Restrictions.Le("StartDate", effectiveDate));
placementCriteria.Add(Restrictions.Ge("EndDate", effectiveDate));
placementCriteria.SetFetchMode("CaseClient.CaseFile", FetchMode.Eager);
placementCriteria.SetFetchMode("CaseClient.Incomes", FetchMode.Eager); 
placementCriteria.SetFetchMode("CaseClient.ClientProfile", FetchMode.Eager);
placementCriteria.SetFetchMode("CaseClient.ClientProfile.Person", FetchMode.Eager);
placementCriteria.SetFetchMode("VendorService", FetchMode.Eager);
placementCriteria.SetFetchMode("VendorService.Vendor", FetchMode.Eager);

using (var session = OpenSession())
{
    using (var tx = session.BeginTransaction())
    {
        residentialPlacements = placementCriteria.GetExecutableCriteria(session).List<ResidentialPlacementClientService>();
    }
}

The "Incomes" property on my is populated correctly.

Now when I add criteria on incomes, the property is no longer being fetched eagerly.

var placementCriteria = DetachedCriteria.For<ResidentialPlacementClientService>();
placementCriteria.Add(Restrictions.Le("StartDate", effectiveDate));
placementCriteria.Add(Restrictions.Ge("EndDate", effectiveDate));
placementCriteria.SetFetchMode("CaseClient.CaseFile", FetchMode.Eager);
placementCriteria.SetFetchMode("CaseClient.Incomes", FetchMode.Eager); 
placementCriteria.SetFetchMode("CaseClient.ClientProfile", FetchMode.Eager);
placementCriteria.SetFetchMode("CaseClient.ClientProfile.Person", FetchMode.Eager);
placementCriteria.SetFetchMode("VendorService", FetchMode.Eager);
placementCriteria.SetFetchMode("VendorService.Vendor", FetchMode.Eager);


var caseClientCriteria = placementCriteria.CreateCriteria("CaseClient", JoinType.InnerJoin);

var incomesCriteria = caseClientCriteria.CreateCriteria("Incomes", JoinType.InnerJoin);
incomesCriteria.Add(Restrictions.Le("StartDate", effectiveDate));

incomesCriteria.Add(Restrictions.Or(Restrictions.Ge("EndDate", effectiveDate),
                                    Restrictions.IsNull("EndDate")));

incomesCriteria.Add(Restrictions.Eq("IncomeType", incomeType));

using (var session = OpenSession())
{
    using (var tx = session.BeginTransaction())
    {
        residentialPlacements = placementCriteria.GetExecutableCriteria(session).List<ResidentialPlacementClientService>();
    }
}

Why does NHibernate do this? How can I change my query/criteria so that the property is fetched eagerly?

Thanks.

Answer 1

if you have filters on an association then NH cant be sure that all entities of the association are returned to initialize the association collection. you can issue a Select for the ids and then fetch the entities with associations eagerly

...
placementCriteria.SetProjection(Projections.Id());

residentialPlacements = session.CreateCriteria<ResidentialPlacementClientService>()
    .Add(Subqueries.In("Id", placementCriteria))
    .SetFetchMode("CaseClient.CaseFile", FetchMode.Eager);
    .SetFetchMode("CaseClient.Incomes", FetchMode.Eager); 
    .SetFetchMode("CaseClient.ClientProfile", FetchMode.Eager);
    .SetFetchMode("CaseClient.ClientProfile.Person", FetchMode.Eager);
    .SetFetchMode("VendorService", FetchMode.Eager);
    .SetFetchMode("VendorService.Vendor", FetchMode.Eager);
    .List<ResidentialPlacementClientService>();