Hi all,

I've a problem mapping my objects. Let's imagine you have a product class and a category class.
Product class has a Category property and category class has a Product
So when I check Product.Category property I have the category linked to the product or Null value if no category is linked.
When I check the Category.Product property, I have the product linked to that category.
My example is quite bad because a category should contain many products but it's not what i want, i want a one-to-one relation.

If I delete a product, all is ok.
But when I want to delete a category, I have an error. I would like to make NHibernate delete the category from its table and to set Ref_IdCategory value to null for the product concerned by this deleted category.

Here is my mapping :

Product :


Category :


Do you have an idea about the mistake I made ?
Thanks
BR

As long as you use/need a one-to-one hibernate can't do that. Hibernate will always delete objects, so just the one product that is loaded will be deleted. So you get a violation of the foreign key for the other products in the database that have the same category.

You can use a foreign key with "on delete cascade set null"

Hi Wolli

Thanks for your answer ! Could you please apply what you said to my little example please ? because I don't know where to do that and what I have to change.
Thanks

You have to apply that change to the database (foreign key):

ALTER TABLE <table> WITH CHECK ADD CONSTRAINT <name> FOREIGN KEY(<column>)
REFERENCES <table> (<column>) ON DELETE SET NULL