Hi,
I'm under hb1.2.5
I've 2 tables with a many-to-many relation between :

<class name="com.model.offres.Service" table="services" >
<set
role="forfaits"
table="relations_forfaits_services"
cascade="none"
>
<key column="service_id"/>
<many-to-many
class="com.model.offres.Forfait"
column="forfait_id"
/>
</set>

<class name="com.model.offres.Forfait" table="forfaits" >
<set
role="services"
table="relations_forfaits_services"
cascade="none"
>
<key column="forfait_id"/>
<many-to-many
class="com.model.offres.Service"
column="service_id"
/>
</set>


With this kind of mapping, When I try
Set services = forfait.getServices();
services.remove(oneOfTheServices)
session.update(forfait)
session.flush()

Then the generated sql is a delete in the relations_forfaits_services followed with an insert in this table (the relation is re-built :-(

If I remove the <SET> in the Forfait.class hbm file then It's Ok,
I should keep this kind of bi-directionnality

How can I do ?

Thanks
Franck

Hibernate (and other ORM tools which are "transparent", ie. not CMP) does not implement "managed relationships". You need to adust *both* ends of the association.

Also, if you check the Hibernate documentation, it is recommended that you map one end of the association with inverse="true"