数据集表适配器管理器帮助

我有一个简单的控制台应用程序，我试图更新客户和订单表，我得到一个错误消息:

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Orders_Customers". The conflict occurred in database "CustomerOrder", table "dbo.Customers", column 'Id'.
The statement has been terminated.

我错过了什么明显的吗?

    RsNorthwinds ds = new RsNorthwinds();
    RsNorthwinds.CustomersRow cRow = ds.Customers.NewCustomersRow();
    cRow.Name = "John Smith";
    ds.Customers.AddCustomersRow(cRow);
    RsNorthwinds.OrdersRow oRow = ds.Orders.NewOrdersRow();
    oRow.CustomerId = cRow.Id;
    oRow.OrderDate = "9/26/11";
    ds.Orders.AddOrdersRow(oRow);
    RsNorthwindsTableAdapters.TableAdapterManager tm =
        new DataTableAdapterTester.RsNorthwindsTableAdapters.TableAdapterManager();
    tm.OrdersTableAdapter = new DataTableAdapterTester.RsNorthwindsTableAdapters.OrdersTableAdapter();
    tm.CustomersTableAdapter = new DataTableAdapterTester.RsNorthwindsTableAdapters.CustomersTableAdapter();
    tm.UpdateAll(ds);