Hi to everyone! I'm experiencing a little problem using NHibernate 1.2.0 with Oracle.

I'm using EmptyStringType to fix the emptystring issue but this conflicts with
optimistic-lock="dirty"
setting in the class mapping.

Consider this scenario:
1) a persistent instance of a class has a string property set to string.Empty
2) I modify this property setting a new value (so it becomes dirty and will be checked in the WHERE condition of the subsequent UPDATE query)
3) I Flush the session

What I get is an UPDATE query similar to the following
UPDATE table SET .....
WHERE ID = :p0
AND MyStringColumn = :p1

with p1 parameter set to DBNull.Value. However, this doesn't work because the where condition doesn't return any rows: it should be something like
WHERE ID = :p0
AND MyStringColumn is NULL

but to get this behaviour I should have the string property set to null in step 1 instead of string.Empty.

Consider that I'm working on a legacy DB and Domain and I cannot easily change them. Is there a way to fix the problem? Do I have to build a custom Oracle driver? Or would it be better working with an interceptor?

Thank you in advance.

Marco