title: Web Chat Application Database Scheme
body: <p>I am making a classified like web application where I want to implement a chat message module. While searching on Internet I found a database scheme ERD Diagram.</p>
  
  <p><a href="https://i.stack.imgur.com/ojCy1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ojCy1.png" alt="enter image description here"></a></p>
  
  <p>I am able to understood it but one thing is confusing me is is_from_sender column in message entity . I found the sample data which is <a href="http://pastie.org/8087359#112" rel="nofollow noreferrer">this</a>. 
  Since I am a beginner I need a little explanation how this works , why using is_from_sender? </p>