title: Postgres Duplicate Key Error Code
body: <p>currently I'm using postgresql as my database and I import all the data into the table through MS Excel csv format. All things went out smoothly but the problem is whenever I want to insert additional data into the table for example using the following code:</p>
  
  <pre><code>insert into country (name)
  values ('America');
  </code></pre>
  
  <p>it keeps pop up an error of </p>
  
  <pre><code>ERROR:  duplicate key value violates unique constraint "effect_pkey"
  DETAIL:  Key (country_id)=(1) already exists.
  ********** Error **********
  
  ERROR: duplicate key value violates unique constraint "effect_pkey"
  SQL state: 23505
  Detail: Key (country_id)=(1) already exists.
  </code></pre>
  
  <p>when I keep trying to insert the data, the error getting is similar just the country_id in the error message is increasing. then I can only insert the data when I surpass the existing ID in my table. I would like to know how can I solve this out. Thank you very much.</p>