Problem with NHibernate

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C#

NHibernate

Goal:
Retrieve data into a class with support of stored procedure with nhibernate. You use nhibernate to retrieve the data by using stored procedure.

Problem:
I have followed some instructions (the link to the website is below) but it doesn't work because I retrieve a error message that is:

"An unhandled exception of type 'NHibernate.MappingException' occurred in NHibernate.dll"
"Additional information: Named query not known: sp_retrieveAllProductCategory"

Information:
- http://nhforge.org/blogs/nhibernate/archive/2008/11/23/populating-entities-from-stored-procedures-with-nhibernate.aspx
- I'm using VS 2013 and SQL server 2013.


-----------------------------------

test.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="data_layer" namespace="data_layer">
  <sql-query name="sp_retrieveAllProductCategory">

    <return class="Produkt">
      <return-property column="Produkt_kategori" name="Produkt_kategori" />
      <return-property column="Produkt_kategori_ordningsnummer" name="Produkt_kategori_ordningsnummer" />
    </return>
    exec sp_retrieveAllProductCategory
  </sql-query>
</hibernate-mapping>


----------------------


hibernate.cfg.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
  <session-factory>
    <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
    <property name="dialect">NHibernate.Dialect.MsSql2012Dialect</property>
    <property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
    <property name="connection.connection_string">Data Source=SHAREPOINT01;Initial Catalog=Active_system;Integrated Security=True</property>
    <property name="show_sql">false</property>
    <mapping assembly="data_layer"/>
  </session-factory>
</hibernate-configuration>

-------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NHibernate;
using NHibernate.Cfg;


namespace data_layer
{

    public class NhibernateDataProvider
    {

        public NhibernateDataProvider()
        {
            _sessionFactory = new Configuration().Configure().BuildSessionFactory();
            _session = _sessionFactory.OpenSession();
        }


        private ISessionFactory _sessionFactory;
        private ISession _session;



     
        public IList<Produkt> GetAllEmployee()
        {
            return _session.CreateCriteria<Produkt>().List<Produkt>();
        }


        public void GetNamedQuery()
        {
            IQuery query = _session.GetNamedQuery("sp_retrieveAllProductCategory");


            //             IList<Product> products = query.List<Product>();

            IList<Produkt> products = query.List<Produkt>();



        }

    }

}

-------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace data_layer
{
    public class Produkt
    {
        public virtual string Produkt_kategori { get; set;}
        public virtual int Produkt_kategori_ordningsnummer { get; set;}
    }
}