title: PrimaryKey and AutoIncrement
body: <p>In the following code, what do <code>PrimaryKey</code> and <code>AutoIncrement</code> mean?</p>
  
  <pre><code>using SQLite;
  
  namespace Todo
  {
      public class TodoItem
      {
          [PrimaryKey, AutoIncrement]
          public int ID { get; set; }
          public string Name { get; set; }
          public string Notes { get; set; }
          public bool Done { get; set; }
      }
  }
  </code></pre>