I've spent some times lately with Linq To SQL and have played a bit with the Mapping namespace.

Why I do not like it very much is a matter for a different post. The matter at hand is that I want the power of Linq, and I want the power of NHibernate, and I want the easy road of ActiveRecord.

What do I mean by that? I'd like:

1. query language == Linq
2. persistence engine == NHibernate
3. Mapping == ActiveRecord attributes

the needed prequisites:

1. Linq (framework => framework.Version >= 3.5)
2. NHibernate.Linq (source => source.getFrom(Rhino-Tools) )
3. Linq for ActiveRecord - Keep on Reading

So, Ayende has kick-started it, and with some help from Bobby Diaz, we have a prototype level NHibernate provider for Linq.

To make it work with ActiveRecord, all you need is to add:

using System;
using Castle.ActiveRecord;
using Castle.ActiveRecord.Framework;
using NHibernate;
namespace NHibernate.Linq
{
    public class ActiveRecordContext : NHibernateContext
    {
        public ActiveRecordContext() : base(null)
        {
            session = GetSession();
        }  
        private ISession GetSession()
        {
            ISessionScope scope = SessionScope.Current;
            if (scope == null)
                throw new InvalidOperationException("You should be in a SessionScope()");
            ISessionFactoryHolder holder = ActiveRecordMediator.GetSessionFactoryHolder();
            return holder.CreateSession(typeof(ActiveRecordBase));
        }
    }
}

and now you can do stuff like:

using (new SessionScope())
{
    ActiveRecordContext context = new ActiveRecordContext();
    var q = 
            from c in context.Session.Linq<Category>()
            select c;  
    foreach (Category c in q)
        Console.WriteLine(c.Name); 
}

Assuming Category has [ActiveRecord] mapping.