title: Use just one table to store more than one type of relation, is efficient?
body: <p>Consider I have a table name <code>Post</code> which stores likes and comments etc. So I want to share a table for comment and likes by storing actual relation in a separate column, example tables :-</p>
  
  <p><strong>Posts</strong></p>
  
  <ul>
  <li>post_id</li>
  <li>post_description</li>
  </ul>
  
  <p>then a relation table :</p>
  
  <ul>
  <li>post_has_
  
  <ul>
  <li>post_id</li>
  <li>user_id</li>
  <li>relation(string : "like", "comment", "shares") etc</li>
  </ul></li>
  </ul>
  
  <p>So by single table we can store more then one relation, all can be manage by application level, not need to create separate table, I want to know is that good idea, or anyone has does that before? Any tradeoffs etc?</p>