I have two tables using a Parent-Child Relation, Child Tables have BLOB data on it.

i have enabled show_sql option.
When i do a session.delete(Parent), Hibernate prints that he's loading all child objects with a "Select", of course, those BLOB objects get loaded and that makes it take a big amount of time. After the "select", hibernate prints some "delect" messages. My question is: Is there any way to cascade delete a parent, and based in the foreign key of each child delete those childs, without the need to load them first.

Someone submited this bug, is related to this or not?
http://jira.nhibernate.org/browse/NH-611

And, if there's no solution how do you it?

Thanks, and sorry my englich

This problem will exists with big BLOBs, CLOBs, and large sets of data. I once tried to clear out a staging table that help a few million records with an HQL query like this:
"delete from MyClass"

Bad move, I watched my page file grow and grow as the enture table was loaded into the cache for a delete.

For cases such as these, I typically will enlist a ado command into the current NHibernate transaction, do my delete with straight ADO, then return control to the rest of the NHibernate-based code. The only issue here is that the work done with the enlisted command is unmanaged so NHibernate knows nothing about the change in the DB's state (but it still is in the context of the working transaction. I'll often flush before such operations and call session.Clear after.

I wrote something on this a while back:
http://www.lostechies.com/blogs/joshua_ ... ction.aspx

hope that answers your question.