get property count with entity using nhibernate - nhibernate

Question

can I am hoping someone can point me to the right direction on how to get count of a property and the entity using a single trip to sql.
public class Category
{
public virtual int Id { get; private set; }
public virtual string Description { get; set; }
public virtual IList<Article> Articles { get; set; }
public virtual int ArticlesCount { 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 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();
Cache.ReadWrite();
}
}
My goal is to get the all Categories and the count of the associated articles if there is any.
I have tried this
ICriteria crit = session.CreateCriteria(typeof(Category));
crit.SetProjection(Projections.ProjectionList()
.Add(Projections.Property("Description"), "Description")
.Add(Projections.Count("Articles"), "ArticlesCount"));
crit.SetResultTransformer(Transformers.AliasToBean (typeof(Category)));
var aa=crit.List();
unfortunately the generated sql shows the count of the Category table not the Articles list.
Thanks

Answer 1

You could use a multi-query, multiple sql statements but it is one trip to the database.
Here is an example from the nhibernate documentation:
https://www.hibernate.org/hib_docs/nhibernate/1.2/reference/en/html/performance.html
IMultiQuery multiQuery = s.CreateMultiQuery()
.Add(s.CreateQuery("from Item i where i.Id > ?")
.SetInt32(0, 50).SetFirstResult(10))
.Add(s.CreateQuery("select count(*) from Item i where i.Id > ?")
.SetInt32(0, 50));
IList results = multiQuery.List();
IList items = (IList)results[0];
long count = (long)((IList)results[1])[0];
Maybe not exactly what you were thinking.