cannot simple "delete from"

pierre-yves · **Posted:** Thu Mar 04, 2004 7:26 am

Following the topic on select and delete :
[url]http://forum.hibernate.org/viewtopic.php?t=926955[/url]

I understand that Hibernate has to do some Lifecycle staff, but then in a one to many relationship if I want to delete all the associated objects without deleting the owner, hibernate has to select all the objects and then delete one by one ! This is not a case of mass process, and I don't want to use JDBC since I would loos the Object/DB mapping of Hibernate ...

Here a sample code :

[code]Session session = sf.openSession();
session.delete("from Kids as detachedObjects where detachedObjects.parent.id = ?", parentid,Hibernate.long);
session.flush();
session.connection().commit();[/code]

Maybe this is wrong way to handle that delete ?
py

pierre-yves · **Posted:** Thu Mar 04, 2004 11:26 am

I tried a different strategy :
with a cascade mode sets to "all-delete-orphan"
and the following code

Code:

Session session = sf.openSession();
session.load(parent);
parent.getKids().clear();
session.save(parent);
session.flush();
session.connection().commit();

Mapping:

Code:

<class name="Parent"
        table="PARENT"
        dynamic-update="false"
        dynamic-insert="false"
        discriminator-value="null"    >
        
      <set name="kids"
            lazy="true"
            inverse="true"
            cascade="all-delete-orphan"
            sort="unsorted">

              <key column="PARENT_ID" />

              <one-to-many class="Kid"              />   
        </set>
   </class>
    <class name="Kid"
        table="KID"
        dynamic-update="false"
        dynamic-insert="false" >
        <many-to-one   name="Parent"
            class="Parent"
            cascade="none"
            outer-join="auto"
            update="true"
            insert="true"
            column="PARENT_ID"
            not-null="true" />
    </class>

I get only one select of parent, one select for all kids and one delete for all kids. It is much better, but still Hibernate has to load all the Kids instances in session. I don't think there is any way to avoid that.

emmanuel · **Posted:** Fri Mar 05, 2004 5:15 am

pierre-yves wrote:

but still Hibernate has to load all the Kids instances in session. I don't think there is any way to avoid that.

Correct