Hi!

I have a problem.:-) i have a many-to-many assosiation between user and Flavour means a user can tell us which flavours he likes( vanilla, chocolat etc.)
now if i delete my user, i would like to delete his entry in the table User_flavour.. but logically i dont want to delete my flavours in my flavours table...

how can i solve that?

i think i have to find the correct cascade values...but which one ...:-)

Thanks a lot!

User.hbm.xml

<set name="flavours" table="user_flavour" cascade="all">
<key column="u_id"/>
<many-to-many class="criteria.Criteria" column="criteria_id"/>
</set>

Flavour.hbm.xml

<set name="users" table="user_flavour">
<key column="flavour_id"/>
<many-to-many class="user.User" column="u_id"/>
</set>

Use the "all" cascade style. In Hibernate2 it is not possible to cacade across a many-to-many such that the "far entity" is deleted. "all" will simply remove the row from the association table.

I tried it with cascade="all" in my set on user side, but it delets the flavours of my user, the flavours in my flavour table and in the table user_flavour all entries, that have the same flavour like my user...*sniff*:-)

is it correct, that it doesnt depend on which "side"( flavour or user) i place the cascade property?

hi everyone.
i' ve got the same problem, but with a slightly different mapping of the many-to-many relationship: in fact i used an idbag to realize a unidirectional many to many relationship from father to children, allowing multiple instance of the same child to be added and treated correctly in the collection.
here it is the mapping i' ve got (i' ve changed class names for better comprehension ):
-> Hibernate 2.1.6 <-


<class name="Father" table="father" mutable="true">
<id name="id" column="fat_id" type="java.lang.Integer" >
<generator class="native">
......
</generator>
</id>
......
<idbag name="children" table="father_son" lazy="false" outer-join="true" cascade="all" >
<collection-id type="java.lang.Integer" column="fat_chi_id">
<generator class="hilo">
</generator>
</collection-id>
<key column="fat_id"/>
<many-to-many column="chi_id" class="Child" outer-join="true"/>
</idbag>
</class>

<class name="Child" table="child" mutable="true">
<id name="id" column="chi_id" type="java.lang.Integer" >
<generator class="native">
.......
</generator>
</id>
.........
</class>

well, as previously reported, a delete command called on a Father persistent object actually remove both the link table entries and the "child" table ones.
I think this is an unwanted behavior, isn' t it?
I appriciate further contribution.
Thanks.

here i go again.
i' ve found ( maybe already well-known from ages :D ) that the desired behaviour may be obtained from the previous mapping just by changing the cascade of the many-to-many collection from "all" to just "save-update".
hibernate itself will eliminate just the father and his entries in the link-table, leaving all the child up and running in their own table.

Hope that can help someone.
See ya.

Same problem here. I already discovered the cascade="save-update" option. But, when i try to delete a Flavour i get a database error. Apparently the Flavour is deleted, but the associated records in the UserFlavour table are not. When i delete a User the associated records in the UserFlavour are deleted.

Is it possible to use an unidirectional many-to-many and be able to delete both sides of the many-to-many?