title: SQL Server 2005 Unique constraint on two columns
body: <p>How do you add a unique constraint in SQL Server 2005 to two columns?  So lets say that I have:</p>
  
  <pre><code>PK, A, B ...
  x1  1  1
  x2  1  2
  x3  2  1
  x4  2  2
  </code></pre>
  
  <p>I should not be able to add another row 'x5' and have the values for A and B be 1,1 as they are already in the database in x1?</p>
  
  <p>Ok we managed to get it to work and thanks to OMG.  Go to the table view, select the two columns, right click and select 'indexes/keys' - general tab, select the columns you want to be unique and then set 'is unique' to true.  This is using the table designer.</p>
  
  <p>Thanks.</p>