Subclass to map additional column of table

I have entity class A and Fluent NHibernate map for it AMap which maps some columns from database table (a few fields are missing). 开发者_开发技巧I would like to create class B which inherits from A (to not break relations with other entities) and map for it to allow access to columns not mapped by base class. The problem is that I cannot change any line of code in base classes (A and AMap). Is there any solution for this problem?

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im not sure how you wanna use it but this could do

class B : A
{

}

class BMap : ClassMap<B>
{
    public BMap()
    {
        Table("A's tablename");
        ...
    }
}

then this should be possible

someEntity.ListOfAs.Add(new B());

dont know if there are problems down the road though

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As far as I understand the requirement, this is a simple table per class hierarchy mapping. You'll need a discriminator column for that.

For the mapping see the last example on that page: Fluent Wiki.