title: Liquibase diff change sets and a database
body: <p>I am developing and have made changes to a db. Before I commit I have to add the change to my change sets. So I do <code>liquibase --url="...;name=db_dev" diff</code> but it asks me for reference parameters. However I do not want to compare the url db with another db. I want to compare the change sets (files) with a target db.</p>
  
  <p>Is this possible?</p>