title: Why are relational databases needed?
body: <p>Specifically thinking of web apps, </p>
  
  <p><strong>(1) why are relationships(ie:foreign keys) in RDBMS even useful?</strong></p>
  
  <p>The web apps I write have logic built-in that validates user input against required fields. I see no real use for foreign keys and thus no real use for relational databases.</p>
  
  <p>Besides, if I were to put all the required field validation logic in the RDBMS(ie:MySQL) it would simply return a vague error. At least with PHP-based validation I know which field is missing and I can notify the user(though with Javascript-based validation this would almost NEVER happen anyway).</p>
  
  <p><strong>(2) Was there a point in the past where RDBMS were useful for some reason or is there a reason they are useful now that I'm not aware of?</strong></p>
  
  <p>I really need some insight on this topic. I'm simply can't come up with a good answer.</p>