title: Difference between DbNull.Value and DbNull.Value.ToString()
body: <p>I wanted to learn which usage is true?</p>
  
  <pre><code>if(!string.IsNullOrEmpty(parentID))
     cmd.Parameters.Add(new SqlParameter("@ParentSesID", parentID));
  else
     cmd.Parameters.Add(new SqlParameter("@ParentSesID", DBNull.Value));
  </code></pre>
  
  <p>OR</p>
  
  <pre><code>if(!string.IsNullOrEmpty(parentID))
     cmd.Parameters.Add(new SqlParameter("@ParentSesID", parentID));
  else
     cmd.Parameters.Add(new SqlParameter("@ParentSesID", DBNull.Value.ToString()));
  </code></pre>