title: What is the difference between an entity relationship model and a relational model?
body: <p>I was only able to find the following two differences:</p>
  
  <ol>
  <li>The relationships in an E-R model are explicitly defined, while they are implicit in a relational model.</li>
  <li>Relational models require an intermediate table (often called a "junction table") to hold two foreign keys that implement the many-to-many relationship.</li>
  </ol>
  
  <p>And why do we use the relational model, when we have an E-R diagram ?</p>