title: Doctrine Relations in mysql
body: <p>I have a question for bulding entity classes with doctrine and designing a database in mysql.</p>
  
  <p>Here is a Image whitch shows the entity classes in PHP like they should be.
  <a href="http://i.stack.imgur.com/vTHS9.png" rel="nofollow">PHP Entity Classes</a></p>
  
  <p>But how i have to design this i mysql?
  Mysql could not save whole objects. Instead mysql will only store the ids from the objects in the table "supermarket" i think. But is that true?</p>
  
  <p>So how i have to design the mysql tables?</p>