[DefaultClassOptions]
  [RuleCombinationOfPropertiesIsUnique("NameUnique", DefaultContexts.Save, "Name1, Name2, Name3")]
  public class Products : BaseObject
  {
    private string name1;
    private string name2;
    private string name3;
    private decimal price;
    private DateTime date;
    …
    public string Name1
    {
      get { return name1; }
      set { SetPropertyValue("Name1", ref name1, value); }
    }

    public string Name2
    {
      get { return name2; }
      set { SetPropertyValue("Name2", ref name2, value); }
    }

    public string Name3
    {
      get { return name3; }
      set { SetPropertyValue("Name3", ref name3, value); }
    }
    …
  }