var q = this.Session.CreateQuery(@"update Contact set Selection = REPLACE(';' + Selection + ';', :fromPara, :toPara) where ';' + Selection + ';' like :fromWhere");
q.SetParameter("fromPara", ";" + from + ";");
q.SetParameter("toPara", ";" + to + ";");
q.SetParameter("fromWhere", "%;" + from + ";%");
q.ExecuteUpdate();