NHibernate Transactions: Is the INSERT-UPDATE_DELETE order for a batch documented somewhere?

Question

Preface: This question is a derivative of this answer, speaking specifically about NHibernate instead of Hibernate.

As to Hibernate, javadoc to org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(EventSource) says:

Execute all SQL and second-level cache updates, in a special order so that foreign-key constraints cannot be violated:

1. Inserts, in the order they were performed
2. Updates Deletion of collection elements
3. Insertion of collection elements
4. Deletes, in the order they were performed

My Questions:

1. If it applies to Hibernate, does this order apply to NHibernate too?
2. Is this deterministic order documented somewhere?

Also - If this behavior is DBMS-specific, I'm using SQL Server.

Answer 1

The documentation of NHibernate 3.3 is in detail describing the steps when the Session.Flush is called (point 9.6). In case of session.FlushMode = FlushMode.Commit; this is how the transaction batch will be executed:

• http://nhibernate.info/doc/nhibernate-reference/manipulatingdata.html#manipulatingdata-flushing

The steps are:

• all entity insertions, in the same order the corresponding objects were saved using ISession.Save()

• all entity updates

• all collection deletions

• all collection element deletions, updates and insertions

• all collection insertions

• all entity deletions, in the same order the corresponding objects were deleted using ISession.Delete()

I am mostly using SQL Server (2008) and can say that this is working this way..