title: ORM and DAO in PHP
body: <p>I am a PHP developer and I am familiar with ORM (Doctrine and Propel), but I seldom heard about DAO. What are  the differences and relationship between ORM and DAO from PHP development perspective?</p>
  
  <p>If I use Symfony to develop very large and complex projects, will that be better if I use DAO? (ORM is somehow heavy I think, but I know little about DAO)</p>