I&#x27;m not sure I understand; doesn&#x27;t<p><pre><code>  BOOK.LANGUAGE.eq(&quot;DE&quot;)
</code></pre>
mean something like<p><pre><code>  Book.Language = &#x27;DE&#x27;
</code></pre>
in SQL? That&#x27;s certainly a boolean expression. I&#x27;ve only started reading the manual, though, so it&#x27;s possible I got the semantics wrong, but I&#x27;ve had SSMS point out to me this sort of thing before.