I am trying to figure out what I thought was just a simple one to many mapping using fluent Nhibernate. I hoping someone can point me to the right directory to achieve this one to many relations I have an articles table and a categories table Many Articles can only belong to one Category Now my Categores table has 4 Categories and Articles has one article associated with cateory1

here is my setup.

using FluentNHibernate.Mapping;
using System.Collections;
using System.Collections.Generic;

namespace FluentMapping
{
    public class Article
    {

        public virtual int Id { get; private set; }
        public virtual string Title { get; set; }
        public virtual Category Category{get;set;}
    }
    public class Category
    {
        public virtual int Id { get; private set; }
        public virtual string Description { get; set; }
        public virtual IList<Article> Articles { get; set; }
        public Category()
        {
            Articles=new List<Article>();
        }

        public virtual void AddArticle(Article article)
        {
            article.Category = this;
            Articles.Add(article);
        }
        public virtual void RemoveArticle(Article article)
        {
            Articles.Remove(article);
        }

    }
    public class ArticleMap:ClassMap<Article>
    {
        public ArticleMap()
        {
            Table("Articles");
            Id(x => x.Id).GeneratedBy.Identity();
            Map(x => x.Title);
            References(x => x.Category).Column("CategoryId").LazyLoad();

        }
        public class CategoryMap:ClassMap<Category>
        {
            public CategoryMap()
            {
                Table("Categories");
                Id(x => x.Id).GeneratedBy.Identity();
                Map(x => x.Description);
                HasMany(x => x.Articles).KeyColumn("CategoryId").Fetch.Join();
            }
        }
    }
}

if I run this test

[Fact]
    public void Can_Get_Categories()
    {
        using (var session = SessionManager.Instance.Current)
        {
            using (var transaction = session.BeginTransaction())
            {
                var categories = session.CreateCriteria(typeof(Category))
                              //.CreateCriteria("Articles").Add(NHibernate.Criterion.Restrictions.EqProperty("Category", "Id"))                                
                .AddOrder(Order.Asc("Description"))
                              .List<Category>();

            }
        }
    }

I am getting 7 Categories due to Left outer join used by Nhibernate any idea what I am doing wrong in here? Thanks [Solution] After a couple of hours reading nhibernate docs I here is what I came up with

var criteria = session.CreateCriteria(typeof (Category));
                    criteria.AddOrder(Order.Asc("Description"));
                    criteria.SetResultTransformer(new DistinctRootEntityResultTransformer());
var cats1 = criteria.List<Category>();

Using Nhibernate linq provider

 var linq = session.Linq<Category>();
                    linq.QueryOptions.RegisterCustomAction(c => c.SetResultTransformer(new DistinctRootEntityResultTransformer()));
                    var cats2 = linq.ToList();