title: What decides Liquibase changeset execution order
body: <p>I have Googled a bit and all I have found is that the order of changeset executions depends on their order in the file they are placed.</p>
  
  <p>Below is a list of changesets in the same file:</p>
  
  <pre><code>&lt;changeSet id="A" author="abc"&gt;
  &lt;/changeset&gt;
  &lt;changeSet id="B" author="abc"&gt;
  &lt;/changeset&gt;
  </code></pre>
  
  <p>Is the order of execution decided based on <em>id</em> or the order in which they are placed? Also, what if the <code>&lt;changeSet&gt;</code> are in different files, what will be the order of execution?</p>