title: Table with only one column or add a numeric primary key?
body: <p>Let's say I need a simple table with account id and no other information. There are two ways to do it:</p>
  
  <pre><code>id varchar(255) PRIMARY KEY
  </code></pre>
  
  <p>Or to add a numeric primary key:</p>
  
  <pre><code>id int PRIMARY KEY
  accountId varchar(255) UNIQUE NOT NULL
  </code></pre>
  
  <p>What are the advantages / disadvantages of both approaches and which one would you choose and why?</p>
  
  <p>What implications does the first solution has to maintainability (what if we need to change the id for a single row) and for performance?</p>