How does NHibernate handle cascade="all-delete-orphan"?

Posted by Johannes Rudolph on Stack Overflow See other posts from Stack Overflow or by Johannes Rudolph
Published on 2010-05-14T17:02:13Z Indexed on 2010/05/14 17:04 UTC
Read the original article Hit count: 493

Filed under:

nhibernate

|

cascade

I've been digging around the NHibernate sources a little, trying to understand how NHibernate implements removing child elements from a collection. I think I've already found the answer, but I'd ideally like this to be confirmed by someone familiar with the matter.

So far I've found AbstractPersistentCollection (base class for all collection proxies) has a static helper method called GetOrphans to find orphans by comparing the current collection with a snapshot.

The existence of this method suggests NHibernate tries to find all oprhaned elements and then deletes them by key. Is this correct, in terms of the generated SQL?

© Stack Overflow or respective owner

Related posts about nhibernate

How can I eager-load a child collection mapped to a non-primary key in NHibernate 2.1.2?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I have two objects with a many-to-many relationship between them, as follows: public class LeftHandSide { public LeftHandSide() { Name = String.Empty; Rights = new HashSet<RightHandSide>(); } public int Id { get; set; } public string Name { get; set;… >>> More
Nhibernate transactions:Avoiding Nhibernate dependency in the service layer

as seen on Stack Overflow - Search for 'Stack Overflow'
One of practices advocated by Nhibernate experts is to do all actions in inside a transaction. In a typical 3 tier web architecture, Nhibernate depedency is limited the data layer. In such a case is it fine to use using (var tr = NHibernateSession.Current.BeginTransaction()) { at the controller… >>> More
Nhibernate 2.1 and mysql 5 - InvalidCastException on Setup

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello there, I am trying to use NHibernate with Spring.Net und mySQL 5. However, when setting up the connection and creating the SessionFactoryObject, I get this InvalidCastException: NHibernate seems to cast MySql.Data.MySqlClient.MySqlConnection to System.Data.Common.DbConnection which causes… >>> More
Series of abstract classes and NHibernate

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello, and first off thanks for your time to look at this. For a research project I'm working on, I have a somewhat complex design (which I've been given) to persist to a database via NHibernate. Here's an example of the class hierarchy: TransitStrategy, TransportationCompany and TransportationLocation… >>> More
Using Time columns with NHibernate, Fluent NHibernate and SQL Server 2008

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello, I have a table with a time column in my SQL Server 2008 database. The property of the object I'm trying to map to is a TimeSpan. How can i tell FluentNHibernate to use the TimeAsTimeSpan NHibernate type, so that I don't have cast problems? >>> More

Related posts about cascade

nhibernate will not cascade delete childs

as seen on Stack Overflow - Search for 'Stack Overflow'
The scenario is as follows, I have 3 objects (i simplified the names) named Parent, parent's child & child's child parent's child is a set in parent, and child's child is a set in child. mapping is as follows (relevant parts) parent <set name="parentset" table="pc-table" lazy="false" … >>> More
Why delete-orphan needs "cascade all" to run in JPA/Hibernate ?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello, I try to map a one-to-many relation with cascade "remove" (jpa) and "delete-orphan", because I don't want children to be saved or persist when the parent is saved or persist (security reasons due to client to server (GWT, Gilead)) But this configuration doesn't work. When I try with cascade… >>> More
Problem with cascade delete using Entity Framework and System.Data.SQLite

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a SQLite DB that is set up so when I delete a Person the delete is cascaded. This works fine when I manually delete a Person (all records that reference the PersonID are deleted). But when I use Entity Framework to delete the Person I get an error: System.InvalidOperationException: The operation… >>> More
Cascade Saves with Fluent NHibernate AutoMapping

as seen on Stack Overflow - Search for 'Stack Overflow'
How do I "turn on" cascading saves using AutoMap Persistence Model with Fluent NHibernate? As in: I Save the Person and the Arm should also be saved. Currently I get "object references an unsaved transient instance - save the transient instance before flushing" public class Person : DomainEntity { … >>> More
Tool to visualize SQL Cascade tree

as seen on Stack Overflow - Search for 'Stack Overflow'
Is there a tool that will let you visualize a SQL Server 2008 cascade tree? I'm having troubles with items not being able to be deleted and I would like to see the path that SQL takes. >>> More