title: Why my tables are not create by Doctrine in symfony
body: <p>I'm learning how to use the php framework symfony 1.4, I'm on the model usage learning.
  I've write the model in the schema.yml, and I've run the following commands :</p>
  
  <p><code>php symfony doctrine:build model</code> which create the model's <code>.class.php</code> files, but i've look on my MySQL database manager and notice that, the database has been create but it still empty. Tables were not created automatically. </p>
  
  <p>So when I try to deal with my datebase, I get exceptions like : </p>
  
  <p><strong>SQLSTATE[42S02]: Base table or view not found: 1146 table 'parlonsaffaires.blog_article' doesn't exists</strong></p>
  
  <p>Can someone help me ?</p>
  
  <p>thanks to any reply </p>