on-delete="cascade" with one-to-one association

Misha_Kan · **Joined:** Tue Jan 04, 2005 5:39 am **Posts:** 37

Hibernate version:3.0.3

Mapping documents:

parent:
...
<one-to-one name="child" class="Child" property-ref="parent"/>
...

child:
...
<many-to-one name="parent" class="Parent" column="PARENT_ID" unique="true"/>
...

I'm mapping objects exactly like it suggested in the reference. But I can't figure out how can I define on-delete="cascade" to trigger DB level deletion of the child object.

Is it possible while DON'T want to use set, list etc ...

Thanks a lot!
Michael.

ramnath · **Posted:** Wed Jun 01, 2005 6:26 am

Hi Misha

Can you make it clear?

You have stated as one-to-one assocation in the subject line.

And in your mapping file you have stated it as

<one-to-one name="child" class="Child" property-ref="parent"/>

<many-to-one name="parent" class="Parent" column="PARENT_ID" unique="true"/>

This is wrong way of mapping.

Let me exact Association?

Misha_Kan · **Joined:** Tue Jan 04, 2005 5:39 am **Posts:** 37

Hi,

Sorry for being unclear :)

The two lines are taken from different mapping files. First one from parent's and second from child's. This is one-to-one bidirectional association.

Look at the hibernate reference - pages 61 bottom - 62 top.

Does anyone have a clue?

Thanks!

ramnath · **Posted:** Wed Jun 01, 2005 7:50 am

Hi Misha

Check this out, No Set, bag for one-to-one association

Mapping for Parent
<one-to-one name="child" class="Child" cascade="all"></one-to-one>

Mapping for Child
<id name="childId" type="int" column="childId">
<generator class="foreign">
<param name="property">parent</param>
</generator>
</id>
<one-to-one name="parent" class="Parent" constrained="true" cascade="save-update"></one-to-one>

Try this and Let me know the results

Misha_Kan · **Joined:** Tue Jan 04, 2005 5:39 am **Posts:** 37

Hi Ramnath,

Thanks a lot for help! But your solution is not what i'm looking for.

In your example (as well as in mine) in case of deletion of the parent object, hibernate will perform the cascading logic and delete the child.

But I don't want it to do it. Instead, I want to use on-delete="cascade" option which will add "on delete cascade" flag to the foreign key in the Database.

The problem is, that this option (on-delete="cascade") could be used only with <key> element, which is part of <set>,<list> ...

Hibernate team?

Misha_Kan · **Joined:** Tue Jan 04, 2005 5:39 am **Posts:** 37

Anyone?

I'm sure that there is a way to do it ...

Misha_Kan · **Joined:** Tue Jan 04, 2005 5:39 am **Posts:** 37

Hibernate team?????????

Can you please respond to this topic ... i need to know if there is something that i'm missing here, or this is unsupported functionality??

gavin · **Posted:** Sun Jun 05, 2005 3:04 pm

on-delete="cascade" is not supported for a <one-to-one>

Misha_Kan · **Joined:** Tue Jan 04, 2005 5:39 am **Posts:** 37

Thanks :)

Why is that? Is it some conceptual consideration, or just a missing feature?

Thanks again for the response!

Michael.