title: Hibernate @DynamicUpdate(value=true) @SelectBeforeUpdate(value=true) performance
body: <p>i am start using this 2 hibernate annotations in my APP.</p>
  
  <pre><code>@DynamicUpdate(value=true)
  @SelectBeforeUpdate(value=true) 
  </code></pre>
  
  <p>first i will try to explain what i understand about it to know if i am right about it.</p>
  
  <pre><code>@DynamicUpdate(value=true)
  </code></pre>
  
  <p>updates only the <code>modified  values</code> in the entity <code>Hibernate needs to track those changes</code></p>
  
  <pre><code>@SelectBeforeUpdate(value=true)
  </code></pre>
  
  <p>creates a <code>select</code> before <code>update</code> to know which properties has been changed this is useful when the entity has been loaded and updated on different sessions <code>Hibernate is out of tracking entity changes</code> </p>
  
  <p>is this 2 affirmations correct?</p>
  
  <p>my main concern is.</p>
  
  <p>in <code>DB performance</code> which is better or faster <strong>updates all the fields in the entity at once</strong> or <code>generate a select to know which columns update and update only the modified columns?</code></p>