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POfluent nhibernate one to many mapping
 

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    <p>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</p> <p>here is my setup. </p> <pre><code>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&lt;Article&gt; Articles { get; set; } public Category() { Articles=new List&lt;Article&gt;(); } 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&lt;Article&gt; { public ArticleMap() { Table("Articles"); Id(x =&gt; x.Id).GeneratedBy.Identity(); Map(x =&gt; x.Title); References(x =&gt; x.Category).Column("CategoryId").LazyLoad(); } public class CategoryMap:ClassMap&lt;Category&gt; { public CategoryMap() { Table("Categories"); Id(x =&gt; x.Id).GeneratedBy.Identity(); Map(x =&gt; x.Description); HasMany(x =&gt; x.Articles).KeyColumn("CategoryId").Fetch.Join(); } } } } </code></pre> <p>if I run this test</p> <pre><code>[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&lt;Category&gt;(); } } } </code></pre> <p>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</p> <pre><code>var criteria = session.CreateCriteria(typeof (Category)); criteria.AddOrder(Order.Asc("Description")); criteria.SetResultTransformer(new DistinctRootEntityResultTransformer()); var cats1 = criteria.List&lt;Category&gt;(); </code></pre> <p>Using Nhibernate linq provider </p> <pre><code> var linq = session.Linq&lt;Category&gt;(); linq.QueryOptions.RegisterCustomAction(c =&gt; c.SetResultTransformer(new DistinctRootEntityResultTransformer())); var cats2 = linq.ToList(); </code></pre>
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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