I have two classes, User and UserAuthorization. When i try to delete a user, the error "a different object with the same identifier value was already associated with the session: 78, of class: User" occurs. Before deleting the User object I delete all UserAuthorizations of the user. I don't know what I can do to resolve this problem.

Hibernate version:
1.0.4

Mapping documents:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
<class name="User" table="User" dynamic-update="false" dynamic-insert ="false">
<id name="ID" column="ID" type="Int32" unsaved-value="0">
<generator class="identity" />
</id>
<property name="Name" column="Name" type="String" length="50" />
<property name="Password" column="Password" type="String"/>
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
<class name="UserAuthorization" table="UserAuthorization" dynamic-insert="false" dynamic-update ="false" batch-size="100">
<id name="ID" column="ID" type="Int32" unsaved-value="0">
<generator class="identity" />
</id>
<many-to-one name="User" column="ID_User" class="User" fetch="join"/>
<many-to-one name="Function" column="ID_Function" class="Function" fetch="join"/>
<property name="Available" column="Available" type="integer"/>
</class>
</hibernate-mapping>

Full stack trace of any exception that occurs:
bei NHibernate.Impl.SessionImpl.Delete(Object obj) in \NHibernate\src\NHibernate\Impl\SessionImpl.cs:Zeile 1213

Hi,

I think the problem is due to the fact that you're fetching the User and the UserAuthorization objects with 2 different sessions, which means that the regular User and the User that is included in the UserAuthorization ("User"-property) are not one and the same object.
When you pass the regular User object to the session after having passed the UserAuthorizations to the session, you're getting this error, which is normal.

A possible solution is to re-assign the User object:


This way, you're asking the session to fetch you the user that is currently present in the session (it's cached and you're using the primary key, so you won't have a roundtrip to the database). When you'll execute the delete, you shouldn't have the error any more.



There are of course other ways to avoid this error, just ensure that you don't use two objects representing the same database record in one session.

Thanks for the quick reply. Now it works fine! :)

I know it's been solved, but FWIW you can also lock (Session.Lock) your original User object to the new session before loading the UserAuthorization.