title: Understanding PrimeFaces process/update and JSF f:ajax execute/render attributes
body: <p>What exactly are <code>process</code> and <code>update</code> in PrimeFaces <code>p:commandXxx</code> components and <code>execute</code> and <code>render</code> in <code>f:ajax</code> tag?</p>
  <p>Which works at the time of validation? What does <code>update</code> attribute do rather than updating value to component from back end? Do <code>process</code> attribute bind value to model? What exactly do <code>@this</code>, <code>@parent</code>, <code>@all</code> and <code>@form</code> in both attributes?</p>
  <p>The example below is working fine, but I am a little confused in basic concepts.</p>
  <pre class="lang-html prettyprint-override"><code>&lt;p:commandButton process=&quot;@parent&quot;
                   update=&quot;@form&quot;
                   action=&quot;#{bean.submit}&quot; 
                   value=&quot;Submit&quot; /&gt;
  </code></pre>