title: What is the difference between DAL, DTO and DAO in a 3 tier architecture style including with MVC
body: <p>Recently I was  learning about ORM (Object Relational Mapping) and the 3 tier architecture style (presentation,business and <strong>data persistence</strong>).
  If I understand correctly, I can separate the <strong>data persistence layer</strong> into DTO and DAO layer. </p>
  
  <p>I would like to understand, how the following parts works together in a data persistence layer.</p>
  
  <ul>
  <li>DAL  (Data Access Layer)</li>
  <li>DTO  (Data Transfer Object)</li>
  <li>DAO  (Data Access Object)</li>
  </ul>
  
  <p>In a top of that I learnt that </p>
  
  <blockquote>
    <p>In larger applications MVC is the presentation tier only of an N-tier
    architecture.</p>
  </blockquote>
  
  <p>I got really confused, how it can be even possible for example in a 3 tier    architecture style where the MVC is the just a presentation tier, and the DTO, DAO, DAL is just a part of data persistence tier. I'm totally lost.</p>
  
  <p>I'd be glad if someone tell me the truth about how does it works together.</p>
  
  <p>Please don't close this question because the many different expressions, I saw it everywhere these things are related to each other basically in big applications and I can't imagine how does it works.</p>
  
  <p>I appreciate any answer!</p>