title: C# EntityFramework6 PostgreSQL To receive database change notifications
body: <p>Sorry for the very rudimentary question.</p>
  <p>I am wondering how to recognize the &quot;change&quot; on the server application side when there is a change from the client application to the database.</p>
  <p>Currently, the server app looks at the database every second to see if the client app has changed the data.</p>
  <p>However, I feel that this is useless processing, and I would like to implement a processing that refers only when there is a change in the database.</p>
  <p>I have implemented this server app in C # and the database uses PostgreSQL, Entity Framework6 (NpgSQL).</p>
  <p>I searched for a similar example in this development environment, but couldn't find it and am wondering what to start with.</p>
  <p>Is it possible to reference the database only when there is a change in the database, like what I want to do?</p>
  <p>And what steps do you need to take to achieve that?
  It's a vague question, so I'm sorry if you bother me.
  Please give me advice.
  Thank you.</p>