NHibernate works without mapping

ISQLQuery query = Session.CreateSQLQuery("SELECT p.*, c.* FROM Product p Left JOIN Product_CustomField c on p.ProductId=c.ProductId");
query.SetResultTransformer(NHibernate.Transform.Transformers.AliasToBean(typeof(Product)));
IList resultList = query.List();

Notes:
Add CusTomField1..5 into Product Class,not need declared in .hbm.xml

Combine with ScalarFields
public class SqlRepository {
...
public IList ListEmployees() {
using (ISession session = _sessionBuilder.GetSession()) {
return session
.CreateSQLQuery(@"
SELECT No_ AS EmployeeNumber, [E-mail Login] AS Username
FROM Employees")
.AddScalar("EmployeeNumber", NHibernateUtil.String)
.AddScalar("Username", NHibernateUtil.String)
.SetResultTransformer(Transformers.AliasToBean())
.List();
}
}
}


Add nHibernate mapping at run time
ISessionFactory sf = new Configuration()
.AddFile("Product.hbm.xml")
.AddFile("Category.hbm.xml")



References:
[1] http://docs.jboss.org/hibernate/core/3.3/reference/en/html/querysql.html
[2] Store procedure http://www.martinwilley.com/net/code/nhibernate/sql.html
[3] Reduced wiring code needed for native sql http://swik.net/Hibernate/Hibernate+GroupBlog/Hibernate+3.1:+Reduced+wiring+code+needed+for+native+sql
[4] AddJoin http://es.efreedom.com/Question/1-1132059/NHibernate-problema-de-AddEntity-y-AddJoin
[5] Native SQL http://knol.google.com/k/fabio-maulo/nhibernate-chapter-14-native-sql/1nr4enxv3dpeq/17#
[6]Fluent NHibernate http://wiki.fluentnhibernate.org/Auto_mapping
[7]Dynamically load .hbm.xml http://www.codeguru.com/forum/showthread.php?t=474322