public static Penjualan FindOneByKode(string kode)
        {
            Database.OpenConnection();
            string select = String.Concat("SELECT * FROM ", nama_tabel, " WHERE kode = @kode");

            Sql.MySqlDataAdapter da = new Sql.MySqlDataAdapter();

            da.SelectCommand = new Sql.MySqlCommand(select, Database.conn);
            da.SelectCommand.Parameters.AddWithValue("@kode", kode);

            Sql.MySqlCommandBuilder cb = new Sql.MySqlCommandBuilder(da);
            DataSet ds = new DataSet();

            da.Fill(ds);
            Database.CloseConnection();

            Penjualan penjualan = new Penjualan();

            if (ds.Tables[0].Rows.Count > 0)
            {
                DataRow dr = ds.Tables[0].Rows[0];
                penjualan.setId(Convert.ToInt32(dr["id"]));
                penjualan.setKode(dr["kode"].ToString());
                penjualan.setCustomer(Customer.FindOneById(Convert.ToInt16(dr["id_customer"])));
                penjualan.setCreatedAt(Convert.ToDateTime(dr["created_at"]));
                penjualan.setUpdatedAt(Convert.ToDateTime(dr["updated_at"]));

                return(penjualan);
            }
            return(null);
        }