title: Should I specify both INDEX and UNIQUE INDEX?
body: <p>On one of my PostgreSQL tables, I have a set of two fields that will be defined as being unique in the table, but will also both be used together when selecting data.  Given this, do I only need to define a UNIQUE INDEX, or should I specify an INDEX in addition to the UNIQUE INDEX?</p>
  
  <p>This?</p>
  
  <pre><code>CREATE UNIQUE INDEX mytable_col1_col2_idx ON mytable (col1, col2);
  </code></pre>
  
  <p>Or this?</p>
  
  <pre><code>CREATE UNIQUE INDEX mytable_col1_col2_uidx ON mytable (col1, col2);
  CREATE INDEX mytable_col1_col2_idx ON mytable (col1, col2);
  </code></pre>