title: How to set unique constraint in Sql Server 2008
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/64981/sql-server-2005-how-create-a-unique-constraint">SQL Server 2005 How Create a Unique Constraint?</a><br>
    <a href="https://stackoverflow.com/questions/13643023/add-unique-constraint-in-sql-server-2008-gui">Add unique constraint in SQL Server 2008 GUI?</a>  </p>
  </blockquote>
  
  
  
  <p>I have a table in Sql Server 2008 named customer.To the email field I want to add a unique constraint-so that email should not be repeated (not using query). I tried in the way as shown in the image and is not able to set the constraint. Please help.
  <img src="https://i.stack.imgur.com/VQMKA.png" alt="enter image description here"> </p>