title: Is it valid to combine a form POST with a query string?
body: <p>I know that in most MVC frameworks, for example, both query string params and form params will be made available to the processing code, and usually merged into one set of params (often with POST taking precedence).  However, is it a valid thing to do according to the HTTP specification?  Say you were to POST to:</p>
  
  <pre><code>http://1.2.3.4/MyApplication/Books?bookCode=1234
  </code></pre>
  
  <p>... and submit some update like a change to the book name whose book code is 1234, you'd be wanting the processing code to take both the <code>bookCode</code> query string param into account, and the POSTed form params with the updated book information.  Is this valid, and is it a good idea?</p>