/// <summary> /// Update the shipping date for a single order /// </summary> /// <param name="oldOrder">The old version of the order, for the order ID</param> /// <param name="newDate">The new version of the date</param> public static void UpdateOrder(Order oldOrder, DateTime?newDate) { using (SqlConnection conn = NorthwindDB.GetConnection()) // get the connection to the DB { string query = "UPDATE Orders SET ShippedDate=@ShippedDate WHERE OrderID = @OrderID"; // we'd only ever change shipped date in this application using (SqlCommand cmd = new SqlCommand(query, conn)) // initialize and use the query object { cmd.Parameters.AddWithValue("@OrderID", oldOrder.OrderID); // if the date is null, use DBnull. Otherwise use the date if (newDate == null) { cmd.Parameters.AddWithValue("@ShippedDate", DBNull.Value); } else { cmd.Parameters.AddWithValue("@ShippedDate", newDate); } conn.Open(); cmd.ExecuteNonQuery(); // run the command } } }