Hi! I have a parent/child relationship in the same table. When an item is deleted, I want all its children to be deleted, too. If I delete an item with no children, all works fine, but when the item has one subitem or more, it complains with this exception:

ERROR: update or delete on "cm_category" violates foreign key constraint "fka01e3933afbcd1cf" on "cm_category"

The database table is as follows:

CREATE TABLE cm_category
(
id int8 NOT NULL,
id_parent_category int8,
CONSTRAINT cm_category_pkey PRIMARY KEY (id),
CONSTRAINT fka01e3933afbcd1cf FOREIGN KEY (id_parent_category) REFERENCES cm_category (id) ON UPDATE NO ACTION ON DELETE NO ACTION
)
WITH OIDS;

And here is the mapping:

<hibernate-mapping>
<class
name="mycontent.manager.Category"
table="cm_category"
proxy="mycontent.manager.Category"
dynamic-update="false"
dynamic-insert="false"
>

<id
name="id"
column="id"
type="java.lang.Long"
>
<generator class="native">
</generator>
</id>

<set
name="children"
lazy="true"
inverse="true"
cascade="all-delete-orphan"
sort="unsorted"
>

<key
column="id_parent_category"
/>

<one-to-many
class="mycontent.manager.Category"
/>
</set>

<many-to-one
name="parent"
class="mycontent.manager.Category"
cascade="none"
outer-join="auto"
update="true"
insert="true"
column="id_parent_category"
/>


</class>

</hibernate-mapping>

If I set inverse="false" then the item is deleted but its children are left with no parent. What's wrong here?

Thanks in advance

Please follow the chapter about parent/child relationships in the reference documentation step by step.

I had followed that chapter step by step already, I swear ;)

I found the problem. I had a "BeanUtils.copyProperties" lost in my code to copy the data from the from to the persistent object (I'm using Struts), and a converter that empties the sets (to prevent form objects from reaching the persistence layer when I do a save). The object that I wanted to delete was beign passed to session.delete() with its children set empty, so hibernate couldn't perform the cascade deletion, and then postgresql was complaining about it. I don't need that "BeanUtils.copyProperties" call at all when doing a delete, now it works fine.

Thanks anyway.

is really bad, you don't know exactly what is happening when you call this things.
Are you using DTO? if yes, sorry for you ;(

Next project try to use your persistent objects directly with a long session per application transaction, you'll have less errors, more control et less code.