title: postgresql: \copy method enter valid entries and discard exceptions
body: <p>When entering the following command:</p>
  
  <pre><code>\copy mmcompany from '&lt;path&gt;/mmcompany.txt' delimiter ',' csv;
  </code></pre>
  
  <p>I get the following error: </p>
  
  <pre><code>ERROR: duplicate key value violates unique constraint "mmcompany_phonenumber_key"
  </code></pre>
  
  <p>I understand why it's happening, but how do I execute the command in a way that valid entries will be inserted and ones that create an error will be discarded?</p>