title: What's the difference between mapping and template in Elasticsearch?
body: <p>We Have two concepts mapping and template in ES. I read the official explanation about these two concepts. I am still confused about it. </p>
  
  <ol>
  <li>In the template, we can define mapping. In this case, why we need mapping?</li>
  <li>If I wanna update mapping, can I just modify it in template?</li>
  </ol>