title: Achieving 3-tier architecture with Symfony PHP
body: <p>In school web projects that I have done until now I have build my applications with a 3-tier approach.
  A data layer, an application and a presentation layer. 
  I have used this architecture with python and java and I want to use it also with php.
  I was quite strict in the communication between layers as these were the requirements of the assignments and I can say that I find it quite good, as when I tried once to switch from mySQL to Mongo db, it was quite easy. I just had to change the code inside the function of my Data Access Object.</p>
  
  <p>As I said before I want to write a bigger application now in php and I downloaded and installed the Symfony2 Framework, which is an MVC framework. My intentions is to test the application with MySQL initial and then switch and test it with Redis.</p>
  
  <p>So myy question is: 
  Can I use the functionality and all the "goodies" of the framework to write a 3 tier architecture application and how could I separate the layers? </p>