Hello,

it seems to me that the cascade options have changed from hibernate 2 to hibernate 3 when deleting an object.

I have an n:m relation that is viewed as a 1:n and an n:1 relation.
So I have 3 Tables, lets call them A, AB, B.

In Object Terms Object A has a Set of Object AB and Object B has a Set of Object AB. AB itself holds a reference to A and a reference to B.

When deleting Object A I also want to delete the Entries in the HashSet automatically (means I want to delete all entries in the HashSet that holds references to Object AB).

My first solution was to delete Object A and hope that Hibernate deletes the references to Object AB in the Table AB. If I do so it depends on the cascade settings what Hibernate will do. If I set cascade="all-delete-orphan" all Objects that have references to AB are deleted. If I use cascade="save-update" I get the error 'deleted object would be re-saved by cascade ...'

Both behaviours are not the expected one.

I get the expected result, if I remove the Objects AB from Object A (means I initialize the Set with a new HashSet and store Object A). The problem with this approach is, that the entries in Table AB are not deleted. Only the reference to Object A is set to NULL.

So now folks, what is the right configuration to let Hibernate cascade from Object A to Object AB and delete Object A as well as all referenced Objects AB in the set of A?

Some good examples would be really good help!

Need help with Hibernate? Read this first:
http://www.hibernate.org/ForumMailingli ... AskForHelp

Hibernate version: 3.0.4

Mapping documents:
<hibernate-mapping>
<class name="at.sozvers.seucc.book.bo.AuthorBO" table="AUTHOR" lazy="false">
<id name="id" column="id" type="java.lang.Long" unsaved-value="null">
<generator class="org.hibernate.id.SequenceGenerator">
<param name="sequence">hibernate_sequence</param>
</generator>
</id>
<version name="version" type="java.lang.Long" column="VERSION" access="property" unsaved-value="undefined"/>
<property name="akadGrad" type="java.lang.String" column="akadGrad" length="30" not-null="false"/>
<property name="geburtsdatum" type="java.lang.String" column="geburtsdatum" length="15" not-null="false"/>
<property name="geschlecht" type="java.lang.String" column="geschlecht" length="1" not-null="false"/>
<set name="bookSet" lazy="false" cascade="all-delete-orphan" sort="unsorted">
<key column="author"></key>
<one-to-many class="at.sozvers.seucc.book.bo.BookAuthorBO"/>
</set>
</class>
</hibernate-mapping>

<hibernate-mapping>
<class name="at.sozvers.seucc.book.bo.BookAuthorBO" table="BOOKAUTHOR">
<id name="id" column="id" type="java.lang.Long" unsaved-value="null">
<generator class="org.hibernate.id.SequenceGenerator">
<param name="sequence">hibernate_sequence</param>
</generator>
</id>
<version name="version" type="java.lang.Long" column="VERSION" access="property" unsaved-value="undefined"/>
<many-to-one name="author" class="at.sozvers.seucc.book.bo.AuthorBO" cascade="delete" outer-join="auto" column="author"/>
<many-to-one name="book" class="at.sozvers.seucc.book.bo.BookBO" cascade="delete" outer-join="auto"column="book"/>
</class>
</hibernate-mapping>

<hibernate-mapping>
<class name="at.sozvers.seucc.book.bo.BookBO" table="BOOK" lazy="false">
<id name="id" column="id" type="java.lang.Long" unsaved-value="null">
<generator class="org.hibernate.id.SequenceGenerator">
<param name="sequence">hibernate_sequence</param>
</generator>
</id>
<version name="version" type="java.lang.Long" column="VERSION" access="property" unsaved-value="undefined" />
<property name="isbn" type="java.lang.String" column="isbn" length="15" not-null="true" />
<property name="title" type="java.lang.String" column="title" length="100" not-null="true" />
<set name="authorSet" lazy="false" cascade="all-delete-orphan" sort="unsorted" >
<key column="book" > </key>
<one-to-many class="at.sozvers.seucc.book.bo.BookAuthorBO"/>
</set>
</class>
</hibernate-mapping>


Code between sessionFactory.openSession() and session.close():
using Spring:
getHibernateTemplate().delete(object);


Full stack trace of any exception that occurs:

Name and version of the database you are using: Postgresql 8.0.1

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

Found one info that told me to clean the set instead of setting it to an empty set. This helps in the case that the whole entry in the AB Table is removed, but still the cascade options are ignored by Hibernate.

Why do I have to clean the set myself. Shouldn't Hibernate do the work for me. Hibernate 2 did quite a better job in this area? I just want Hibernate to cascade to the Table AB and delete the entries that are associated to Table A.

Where are the Hibernate Users around? Did no one had similar problems with Version 3.0.x?

Thx Rene

I am having the exact same problems. Do you have any further information? I think (with my limited hibernate experience) the cascade="delete" on the many-to-one element of the AB object is wrong, you don't want the A and B objects deleted, when the AB object is deleted.

I can't really think about a good solution: When I delete a A object I don't want to tamper with the List of AB objects in B, that defeats the purpose of cascade deletes. Is there any good solution?