If I use nhibernate to map tables 1:1 with no associates, do I still need dynamic proxy etc? -

If I just want to keep things very simple, and just POCO 1:

for example Instead of:

  class class order commands  

where you have:

  order o = new order ( ); O.Items & lt; - Collection of OrderItems that will query DB by using lazy loading  

I have to do this manually:

  order o = myDAO.FindById ( 1); Order items i = myDAO2.FindByOrderId (OID);  

To use this approach, do I need to use the castle.dynamic proxy DLL now and I have to work around a medium trust issue?

If you are not using lazy loading then you do not need a proxy so far That when you download from nhforge, the assemblies are divided into essential and essential-lazy-loading.