after doing some more experiments i can partialy answer this question myself:
by adding an on-delete="cascade" to the sets key element and changing the cascade to "save-update" the hotel gets deleted by using one statement since the DB will take care of the cascading.
Quote:
<set
name="rooms" cascade="save-update" inverse="true">
<key column="HOTEL_REF" not-null="false" on-delete="cascade"/>
<one-to-many class="Room"/>
</set>
still i would like to know if hibernate can issue the delete based on the FK on the hotel instead of the PK of the rooms ?
fab