loquacious

NHibernate Validator and Schema Export question

I'm learning to use NHibernate validator and it's Fluent API (Loquacious). I have noticed is that I can't set an integer property or nullable int property (int?) to be not nullable. Well, why not? In a database, an integer column can have null values. Even worse, when I generate DDL using SchemaExport, the integer column wont be pickin...