title: SQL dont allow duplicate records in table
body: <p>How do I make it not add duplicates?
  I want to make it check by all other columns beside ID.</p>
  
  <p>I want this to be invalid.</p>
  
  <pre><code>ID    col1    col2   col3
  
  1    first   middle  last   
  
  
  ID    col1     col2   col3
  
  2    first   middle  last  
  </code></pre>
  
  <p>I want this to be valid.</p>
  
  <pre><code>ID    col1    col2   col3
  
  1    first   middle  last   
  
  
  ID    col1     col2   col3
  
  2    first    last   middle   
  </code></pre>