hibernate中one-to-many双向中关于update的问题

在更新事件中，怎么做到只能信主表而从表不动。<set name="photo" table="face_standard_photo" lazy="false" inverse="false" cascade="all">
     <key>
        <column name="PERSONNELID" not-null="true"/>
     </key>
     <one-to-many class="com.face.ORM.FaceStandardPhoto"/>
</set>
<many-to-one name="doubtful"
        column="PERSONNELID"
        class="com.face.ORM.FaceDoubtful"
        not-null="true"
        lazy="false"
        cascade="none" />如何解决