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POBitwise operation and Extension method with NHibernate QueryOver
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  1. POBitwise operation and Extension method with NHibernate QueryOver
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    copied!<p>I want to query a table with numeric columns that contains flags.</p> <p>I've built a mapping with NHibernate XML against a SQL Server 2008 database (I show you only interesting part):</p> <p>This is my enum:</p> <pre><code>[Flags] public enum DocsFlag { FLAG_TOREAD = 0, FLAG_READ = 2, FLAG_MANAGED = 4, FLAG_INUSE = 8, FLAG_FORWARDED = 16, FLAG_RESUBMITTED = 32, FLAG_PRINTED = 64, } </code></pre> <p>this is my class:</p> <pre><code>public class MyObject { ... public virtual DocsFlag Flags { get; set; } } </code></pre> <p>Here my class db mapping:</p> <pre><code>&lt;class name="MyObject"&gt; ... &lt;property name="Flags" not-null="true"/&gt; &lt;/class&gt; </code></pre> <p>I want to query with strongly typed <code>QUERYOVER</code> :</p> <pre><code>_session.QueryOver&lt;MyObject&gt;() .Where(x =&gt; x.Error != null &amp; (x.Flags &amp;&amp; (DocsFlag.FLAG_READ | DocsFlag.FLAG_MANAGED | DocsFlags.FLAG_PRINTED)&gt; 0)) .Left.JoinQueryOver&lt;DestinationObj&gt;(m =&gt; m.Destination) .Left.JoinQueryOver&lt;UsersObj&gt;(x =&gt; x.LinkedUser).ToList(); </code></pre> <p>Or simply:</p> <pre><code>.Where (x=&gt; x.Flags &amp;&amp; (DocsFlag.FLAG_READ | DocsFlag.FLAG_MANAGED | DocsFlags.FLAG_PRINTED)&gt; 0) </code></pre> <p>But it doesn't work....</p> <p><strong>What is the best way to query bit flags with nhibernate <code>QueryOver</code>?</strong></p> <p>I tried these solutions:</p> <ol> <li><p>I think to query directly with <code>createSqlQuery</code> but my query are very complex and I want to take advantage of <code>QueryOver</code> API.</p></li> <li><p>I have begin my project with Linq to Nhibernate, but I've found a lot of bugs and I have noticed that there are not full support for query...</p></li> <li><p>Write my own <code>QueryOver</code> extension methods to query flags columns but it's too early for me because I didn't understand how to <code>QueryOver</code> API transform code lambda functions in SQL query (and apply appropriate dialect).</p></li> </ol> <p>Help me to find the best way...</p>
 

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