I have two tables. One table has a many-to-one mapping to the other.
I make a Criteria with selecting from table1 and SetFetchMode for the many-to-one mapping to FetchMode.Join.
When the foreignkey field in the database ist null or has a valid value all works fine. The objects are loaded with only one Join-SQL.
But there are many references in the database (MSSQL) with foreignkey=String.Empty instead of NULL. In this case NHibernate fires one big Join-SQL and a select for every reference which is set to String.Empty. I have about 1000 records, this means it fires 1001 select sqls.
Can i configure that String.Empty is equivalent to NULL or something else?
My many-ton-one mapping:
<many-to-one name="Adresse" not-found="ignore" column="adrnr" access="field.pascalcase-underscore"/>

If i clear not-found="ignore" it works but i want to have null when no reference is set and not a proxy-object.

I don't understand why this is not configurable. Hope that one of the programmers of NHibernate can give me tips how i can change this behaviour. I have no chance to change the behaviour in the database, because there are one another application read and write the tables. And this other application saves non referenced foreign keys as "" (Empty) instead of NULL.

I need a solution!