title: Do I need to close SQL Server connection with the using keyword?
body: <p>I keep finding conflicting results for this question. Let's look at this C# code of running an SQL query:</p>
  
  <pre><code>using (SqlConnection cn = new SqlConnection(strConnectString))
  {
      cn.Open();
  
      using (SqlCommand cmd = new SqlCommand(strSQL, cn))
      {
          cmd.ExecuteNonQuery();
      }
  
      //Do I need to call?
      cn.Close();
  }
  </code></pre>
  
  <p>Do I need to call that last <code>cn.Close()</code>? The reason I'm asking is that in a heavy traffic web app I run out of connections in a pool.</p>