Question

Hello
I’m new with nhibernate, I’d like to fill a treeview with some information
– a list of visit (“visites” in the code) for one customer
– each visit contains a list of bill (“factures” in the code)

I wrote that code :

ISession session = NHibernate.DataAccess.Models.Repository.TSession();

var visites = (from v in session.Query<Visites>()
 where v.Clients.Idclient == lstClients.SelectedValue.ToString()
 && v.Supprime == false
 select v).ToList();

foreach (Visites v in visites)
{
 node = new TreeNode("Visite du " + v.Datevis.ToShortDateString());

 var liste = v.Factures.Where(f => !f.Masque).Where(f => !f.Recup);
 foreach (Factures f in liste)
 {
  node.Nodes.Add("Facture n°" + f.Nofacture.ToString());
 }
}

Please notice that :

1. the list of the visit are filtered (the visit of one customer)
2. the list of the bill are filtered (only the visible bill)

It works well but it is slow, for every visit there is a sql query.
On my old code I made a sql query which retrieve all the visites on the customer left join the visible bill and with the good order I can fill the treeview.

What is the best practice for that query ?

regards

Answer 1

Add batch-size="n" to your mapping for the Visites.Factures collection, where n is the count of collections you want to load at once.

That means you’ll only have a query for each n Visites instances.