title: Unique key vs. unique index on SQL Server 2008
body: <p>I have a table called <code>countries</code> and I define the <code>country_name</code> column to be unique by creating a “Index/Key” of type “Unique Key” on SQL Server 2008 R2. </p>
  
  <p>But I have the following questions:</p>
  
  <ol>
  <li>will creating “Index/Key” of type “Unique Key” automatically create a non-clustered index on this column?</li>
  <li>if I change the type from being “Unique Key” to "Index" and I keep the <code>IsUnique</code> value to be "Yes",, then will there be any differences ?</li>
  <li>so why there are two options “Unique Key” and "Index" I think the two are the same ?</li>
  </ol>