NHibernate Query w/ criteria against collection items - nhibernate

Question

I have the following configuration in the database.
Database Schema
I want to be able to query all the Individuals where they are either an employee or vendor. Of the examples I've seen I can't get any of them to work. The code doesn't throw an error, it just doesn't bring back any records.
Here are the DTO's
public class Individual
{
public virtual int Sid { get; set;}
public virtual string Id { get; set; }
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
public virtual string MiddleInitial { get; set; }
public virtual ISet<Company> Companies { get; set; }
}
public class Company
{
private bool _inactive;
public virtual int Sid { get; set; }
public virtual string Name { get; set; }
public virtual IList<Individual> Individuals { get; set; }
public virtual bool Active
{
get { return !_inactive; }
set { _inactive = value; }
}
public virtual bool IsVendor { get; set; }
}
public class IndividualCompany
{
public virtual Individual Individual { get; set; }
public virtual Company Company { get; set; }
public override bool Equals(object obj)
{
if (obj == null)
return false;
IndividualCompany key = obj as IndividualCompany;
if (key == null)
return false;
if (Individual.Sid == key.Individual.Sid && Company.Sid == key.Company.Sid)
return true;
return false;
}
public override int GetHashCode()
{
int hash = 13;
hash = 7 * hash * Individual.Sid.GetHashCode();
hash = 7 * hash * Company.Sid.GetHashCode();
return hash;
}
}
I have another function that uses these 3 tables and all my Individuals and the collection of Companies gets populated just fine so I know the mapping is working. I just don't know how to add criteria on the child record.
string sql = "from Individual i" +
" inner join fetch i.Companies";
return _session.CreateQuery(sql).List<Individual>();
Here's the query I'd like it to produce.
select i.*
from individual i inner join individual_company_assoc ica
on i.individual_sid = ica.individual_sid
inner join company c
on ica.company_sid = c.company_sid
where c.is_vendor = 0
Here's what I've tried:
public IList<Individual> Get(bool vendorsOnly)
{
try
{
return _session.CreateCriteria<Individual>()
.CreateAlias("Company", "c")
.Add(Restrictions.Eq("c.IsVendor", vendorsOnly))
.List<Individual>();
}
catch (NHibernate.HibernateException)
{
throw;
}
}
I'm not using FluentNHibernate. Any help would be greatly appreciated.

Answer 1

An nHibernate query will not automatically join with other tables, even if you reference columns of a joining table in the query.
You must explicitly state that the query should join with the Company table.
Here's an example which will work. It uses the QueryOver syntax, which is a type-safe wrapper around the Criteria API.
return _session
.QueryOver<Individual>()
.JoinQueryOver<Company>(i => i.Companies>())
.Where(c => c.IsVendor == vendorsOnly)
.TransformUsing(NHibernate.Transform.Transformers.DistinctRootEntity)
.List();