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copied!<p>You would want to use <code><List /></code> instead of <code><Bag /></code></p> <pre><code><bag name="Controls" cascade="all-delete-orphan" lazy="false"> <key column="PageConfigurationId" /> <one-to-many class="WidgetConfiguration" /> <index column="SlotOrder" /> </bag> </code></pre> <p>I notice that you are mapping your collection currently as a <code>Bag</code>. NHibernate supports three kinds of sequenced-collections - <code>Bag</code>, <code>Set</code> and <code>List</code></p> <p>List has ordering semantics, as I guess you are aware, but when no ordering is required, you would normally use a <code>Set</code>.</p> <p>Because a <code>Set</code> mandates that each item is in a collection only once, it is very easy to remove an item using a single delete statement on that item's Id. A <code>Bag</code> does not mandate collection uniqueness, so the only way for NHibernate to delete an item is to delete everything, and then re-add every item that was not the deleted item. (The inverse is adding an item to a <code>Bag</code> can be faster than using a <code>Set</code>, because uniqueness does not have to be enforced)</p> <p>Ayende (one of the main contributors to NHibernate) posted these a while back:</p> <p><a href="http://ayende.com/blog/3943/nhibernate-mapping-set" rel="nofollow">http://ayende.com/blog/3943/nhibernate-mapping-set</a></p> <p><a href="http://ayende.com/blog/4043/nhibernate-mapping-list" rel="nofollow">http://ayende.com/blog/4043/nhibernate-mapping-list</a></p>

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