title: Generate auto ID in postgresql
body: <p>User Table:</p>
  
  <pre><code>    ID  Name
      1   usr1
      2   usr2
      3   usr3
  </code></pre>
  
  <p>In the above table, ID is a primary key. My requirement is while inserting data into the table, I would like to specify only the 
  name like <code>INSERT INTO user VALUES('usr4')</code>. After execute the query, Is there any way to automatically create ID for 'usr4'?</p>
  
  <p>I tried with serial data type. For that also we have to specify the keyword default like <code>INSERT INTO user VALUES(default,'usr4')</code>. So, is there any way to do like <code>INSERT INTO user VALUES('usr4')</code>. NOTE: ID should be unique. </p>