Hi!
First of all, I have been evaluating NHibernate an I really like it
I found it really easy to use.. but maybe I am biased because used to be a user of the original Hibernate for Java ;).

Now... the only disadvantage I have found for NHiberate is that in .NET ints, datetimes, decimals, etc cannot be nulls... so our PONOs (Plain Old .NET Objects) cannot represent a commonly used "database value"

In a Typed DataSet, this is solved by adding "special" properties, that is if for example, there is a property:

Class Person{
public DateTime DateTime BirthDate{
get{}
set{}
}
}

That could be null, then the code generator generates an two extra methods

Class Person{
public DateTime DateTime BirthDate{
get{}
set{}
}

public bool IsBirthDateNull() {
}

public void SetBirthDateNull() {
}
}

So, if I want to check in BirthDate is null, a first go an check if there is a property method named Is[NullablePropertyName]Null, and if is true, it means the database has a null. And If I want to set it as null all I have to do is use the "Set" method.

Now, this pair of method sounds a lot like a property, so it could be generated as:

public bool IsBirthDateNull{
get{}
set{}
}

IMHO this could permit handling nulls without using nullable types... so... my question is... in which files should do you recommend I start hacking to add this "feature"? do you think it is good idea?

IMHO, it will not be easy to add this feature...

Why don't you want to use Nullable Types?

Just use the NullableTypes. You could be confused - the NullableTypes can't actually be set to null. They provide a "HasValue" property, which does the same thing as your IsBirthDateNull() function.

Here is an implementation of what you want using the NullableTypes:



The mapping for this class would then look like this: