title: What does creating a connection between an application and database mean?
body: <p>When we say we have created a connection between a database and an application (that can be stored in connection pool),  what really a "connection" means here? </p>
  
  <ul>
  <li><p>Does it got anything to do with establishing a <code>TCP/ TLS</code> connection?</p></li>
  <li><p>Does it load the database schema with every connection?</p></li>
  <li><p>What happens to a connection (that are already loaded in application connection pool) when the database schema changes, and there is an active transaction going on?</p></li>
  </ul>