title: Advantages and disadvantages of GUID / UUID database keys
body: <p>I've worked on a number of database systems in the past where moving entries between databases would have been made a lot easier if all the database keys had been <a href="http://en.wikipedia.org/wiki/Globally_Unique_Identifier" rel="noreferrer">GUID / UUID</a> values. I've considered going down this path a few times, but there's always a bit of uncertainty, especially around performance and un-read-out-over-the-phone-able URLs.</p>
  
  <p>Has anyone worked extensively with GUIDs in a database? What advantages would I get by going that way, and what are the likely pitfalls?</p>