NHibernate DTO mapping

mapping, nhibernate

Solution

You don't need to map/persist a `DTO` object. It's normaly to readonly data and send to other layer of your application (web services, views, etc...).

You can create a query on the `Person` entity that returns a `PersonDTO` list. Take a look at `SetResultTransformer` method. Try somethin like this:

var query = session.CreateQuery("select p.FirstName, p.Age from Person p order by p.FirstName")
                   .SetResultTransformer(NHibernate.Transform.Transformers.AliasToBean(typeof(PersonDTO)))
                   .List<PersonDTO>();

And your DTO:

public class PersonDTO 
{
   public string FirstName { get; set; }
   public int Age { get; set; }
}

The result of the column on the `hql` query should have the same name of your DTO's properties to NHibernate do the right reflection when construct the DTO and hydrate the object.

Linq

You also can use `linq` to have a `DTO` (or a list of DTOs) as a result. For sample:

var query = Session.Query<Person>().OrderBy(x => x.FirstName)
                   .Select(x = new PersonDTO() { FirstName = x.FirstName, Age = x.Age })
                   .ToList();

Look this article: http://gustavoringel.blogspot.com.br/2009/02/creating-dto-in-nhibernate-hql-using.html

Problem

Original source