title: Postgres: remove check constraint on varchar column
body: <p>I'm coming from a MySQL world and am having a hard time doing things in PostgreSQL.</p>
  
  <p>I have a column which looks like this in my GUI client: <a href="https://i.stack.imgur.com/mIh9m.png" rel="noreferrer"><img src="https://i.stack.imgur.com/mIh9m.png" alt="enum column"></a></p>
  
  <p>I'm not sure if it is an enum column, or a varchar with a constraint (are they the same thing in postgres?)</p>
  
  <p>I want to change the type of the column to a varchar/string. I've tried this:</p>
  
  <pre><code>ALTER TABLE tablename ALTER COLUMN type TYPE character varying(255);
  </code></pre>
  
  <p>but no luck, I still see the constraints on the column</p>