title: Intermediate SQL Table : What for?
body: <p>I'm managing to create my first complicated J2E Solution and in every tutorial I find some sort of intermediary tables usage, like here :</p>
  
  <p>Tables : User, User_Roles, Roles
  While logic would simply add a key to user Table referring to it's role on Roles table, why the usage of that intermediary table ?</p>
  
  <p>I thought it's one or two developpers choice, but everywhere I look for a tutorial, I find this sort of sql schema.</p>
  
  <p>Is it better ? Does it help in something particular ? Speed, security ? Cause from a logic point of view, using one table User and a foreign key to Roles is better.</p>
  
  <p>Thank you</p>