title: Query to determine if columns combine to create a unique key
body: <p>I'm trying to determine if a set of three columns on a table in Oracle would constitute a unique key and could be used in a 1:1 relationship.</p>
  
  <p>If I run this query, and the keys are a unique combination, I should not see a <code>count</code> > 1, correct?</p>
  
  <pre><code>select count(*) from my_table t    
  group by t.a, t.b, t.c
  </code></pre>
  
  <p>Is there a better/alternative way to make this determination?</p>