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PONHibernate one-to-many relationship lazy loading when already loaded
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  1. PONHibernate one-to-many relationship lazy loading when already loaded
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    copied!<p>I have a tree where every node is a Resource class: </p> <pre><code>public abstract class Resource { public virtual Guid Id { get; set; } public virtual Resource Parent { get; set; } public virtual IList&lt;Resource&gt; ChildResources { get; set; } } </code></pre> <p>as you can see this class is abstract and there are many different derived classes from Resource (3 at the moment, more to come). </p> <p>In my database i have a table for Resource, and a table for each class which derives from Resource. These are mapped together with <code>&lt;joined-subclass&gt;</code>. </p> <p>I've read this: </p> <p><a href="http://ayende.com/Blog/archive/2009/08/28/nhibernate-tips-amp-tricks-efficiently-selecting-a-tree.aspx" rel="nofollow noreferrer">http://ayende.com/Blog/archive/2009/08/28/nhibernate-tips-amp-tricks-efficiently-selecting-a-tree.aspx</a></p> <p>and i have the same code as Ayende to load my tree:</p> <pre><code>var resource = UnitOfWork.Current.Session .CreateQuery("from Resource r join fetch r.ChildResources") .SetResultTransformer(new DistinctRootEntityResultTransformer()) .SetReadOnly(true) .List&lt;Resource&gt;(); </code></pre> <p>which is all working fine (all Resources are returned with a single select) However, I'm seeing extra selects occurring as I enumerate a Resource's ChildResources list. </p> <p>Is that because of this?: </p> <p><a href="http://ayende.com/Blog/archive/2009/09/03/answer-the-lazy-loaded-inheritance-many-to-one-association-orm.aspx" rel="nofollow noreferrer">http://ayende.com/Blog/archive/2009/09/03/answer-the-lazy-loaded-inheritance-many-to-one-association-orm.aspx</a></p> <p>Either way, how do I prevent this from happening? </p> <p>Here's the part of the mappings for the relationships (class names trimmed for clarity): </p> <pre><code>&lt;bag cascade="save-update" fetch="join" lazy="false" inverse="true" name="ChildResources"&gt; &lt;key&gt; &lt;column name="Parent_Id" /&gt; &lt;/key&gt; &lt;one-to-many class="Resource" /&gt; &lt;/bag&gt; &lt;many-to-one class="Resource" name="Parent"&gt; &lt;column name="Parent_Id" /&gt; &lt;/many-to-one&gt; </code></pre> <p>Thanks</p> <p><b>UPDATE</b></p> <p>Slight oversight, its only issuing extra selects when enumerating the child collections of the leaf nodes in the tree...</p>
 

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