title: Dropping unnamed constraints
body: <p>I've created some foreign keys without an explicit name.</p>
  <p>Then I've found SQL generated crazy names like <code>FK__Machines__IdArt__760D22A7</code>. Guess they will be generated with different names at different servers.</p>
  <p>Is there any nice function to drop the unnamed FK constraints passing as arguments the tables and the fields in question?</p>