how to delete fk children in nhibernate - nhibernate

Question

I would like to delete the ICollection PriceBreaks from Product.
I'm using the following method. However they dont seem to delete. What am i missing.
When i step thru. i notice that "product.PriceBreaks.Clear();" doesn't actually clear the items. Do i need to flush or something?
public void RemovePriceBreak(int productId)
{
using (ISession session = EStore.Domain.Helpers.NHibernateHelper.OpenSession())
using (ITransaction transaction = session.BeginTransaction())
{
var product = session.Get<Product>(productId);
// i can see 20 PriceBreak records, tho nh prof saids PriceBreak table hasn't been hit
product.PriceBreaks.Clear();
session.SaveOrUpdate(product);
transaction.Commit(); // PriceBreak table is hit here with select statement, no delete?
}
}
Here are my hbm files
<class name="Product" table="Products">
<id name="Id" type="Int32" column="Id" unsaved-value="0">
<generator class="identity"/>
</id>
<property name="CompanyId" column="CompanyId" type="Int32" not-null="true" />
<property name="Name" column="Name"/>
<set name="PriceBreaks" table="PriceBreaks" generic="true" cascade="all-delete-orphan" inverse="true" >
<key column="ProductId" />
<one-to-many class="EStore.Domain.Model.PriceBreak, EStore.Domain" />
</set>
</class>
<class name="PriceBreak" table="PriceBreaks">
<id name="Id" type="Int32" column="Id" unsaved-value="0">
<generator class="identity"/>
</id>
<many-to-one name="Product" column="ProductId" not-null="true" class="EStore.Domain.Model.Product, EStore.Domain" />
</class>
My Entities
public class Product
{
public virtual int Id { get; set; }
public virtual ICollection<PriceBreak> PriceBreaks { get; set; }
public virtual void AddPriceBreak(PriceBreak priceBreak)
{
priceBreak.Product = this;
PriceBreaks.Add(priceBreak);
}
}
public class PriceBreak
{
public virtual int Id { get; set; }
public virtual Product Product { get; set; }
}
Here is the sql from nhprof
//
SELECT product0_.Id as Id0_0_
FROM Products product0_
WHERE product0_.Id = 23 /* #p0 */
and then
SELECT pricebreak0_.ProductId as ProductId1_,
pricebreak0_.Id as Id1_,
pricebreak0_.Id as Id1_0_,
pricebreak0_.ProductId as ProductId1_0_,
FROM PriceBreaks pricebreak0_
WHERE pricebreak0_.ProductId = 23 /* #p0 */
there is no update or select

Answer 1

Product probably needs to be associated with that session. It looks like you are trying to save a detached object. Which means there is no session to track that call to clear the PriceBreaks. Change it to this...
public void RemovePriceBreak(int productId)
{
using (ISession session = EStore.Domain.Helpers.NHibernateHelper.OpenSession())
using (ITransaction transaction = session.BeginTransaction())
{
var product = session.Get<Product>(productId);
product.PriceBreaks.Clear();
session.SaveOrUpdate(product);
transaction.Commit();
}
}
or move the session and transaction management further up. Which would basically eliminate the need for this method.

Answer 2

Have you tried deleting the cascade="all" on the PriceBreak side ?
Have you tried using session.Save() instead of SaveOrUpdate() ?