title: XML - Referencing Other XML Files
body: <p>I'm new to XML, so this may be a fairly easy question to answer.  I was wondering if there is a standard way of referencing external XML files from within other XML files.  Let me give an example.  Say you have a file which defines a single object that holds a large amount of data:</p>
  
  <pre><code>&lt;person&gt;
      &lt;name&gt;John&lt;/name&gt;
      &lt;age&gt;18&lt;/age&gt;
      &lt;hair&gt;Brown&lt;/hair&gt;
      &lt;eyes&gt;Blue&lt;/eyes&gt;
  &lt;/person&gt;
  </code></pre>
  
  <p>For the sake of this question, pretend that person holds loads of other information.  Pretend the file is like 10 MB.</p>
  
  <p>Now, let's say you have another XML file which defines a group:</p>
  
  <pre><code>&lt;group&gt;
      &lt;person&gt;
          &lt;name&gt;John&lt;/name&gt;
          &lt;age&gt;18&lt;/age&gt;
          &lt;hair&gt;Brown&lt;/hair&gt;
          &lt;eyes&gt;Blue&lt;/eyes&gt;
      &lt;/person&gt;
      &lt;person&gt;
          &lt;name&gt;Kim&lt;/name&gt;
          &lt;age&gt;21&lt;/age&gt;
          &lt;hair&gt;Blue&lt;/hair&gt;
          &lt;eyes&gt;Green&lt;/eyes&gt;
      &lt;/person&gt;
      &lt;person&gt;
          &lt;name&gt;Sean&lt;/name&gt;
          &lt;age&gt;22&lt;/age&gt;
          &lt;hair&gt;Black&lt;/hair&gt;
          &lt;eyes&gt;Brown&lt;/eyes&gt;
      &lt;/person&gt;
  &lt;/group&gt;
  </code></pre>
  
  <p>As you can see, if <em>Person</em>'s were very large, the <em>Group</em> file would be extremely large.  So, if we have something like <em>John.xml</em>, is there a <em>standard</em> way to reference it in <em>Group.xml</em> without explicitly defining all of John's data?  I'm sure this is a very broad topic, so feel free to link me to any relevant web pages.  Thanks!</p>