title: Is it bad to use user name as primary key in database design?
body: <p>I was told by a friend:</p>
  
  <blockquote>
    <p>What unique key do you use? I hope you
    are not saving the entire user name
    --- this will use up too much table space! Assign an unique userID to each
    (unique) userNAME and save this userID
    (should be INTEGER UNSIGNED
    auto_increment  or  BIGINT UNSIGNED
    auto_increment). Don't forget to
    create a reference</p>
    
    <p>FOREIGN KEY (<code>userID</code>) REFERENCES
    <code>usertable</code> (<code>userID</code>) in all tables
    using the userID.</p>
  </blockquote>
  
  <p>Is the above statement correct? Why or why not?</p>