I try to delete a large graph of objects (parent/child with many relations on others classes) and The delete function generates many sql SELECT query. It takes more than 15 minutes to finish the operation

My questions are :

It is possible to remove all this sql query ? and How ?

My guess is that your objects are fetched for nHibernate to perform cascading operations and to cascade to the complete object graph it have to be fetched from the database.

15 minutes sounds like a long time to fetch data, how large is your object graph?