Business Rules/Logic

The most robust method to ensure separation between “draft” and “committed” data is physical segregation of draft data in dedicated staging tables. When data is ready to be committed, it is moved from draft tables to the primary database tables. For example, orders in the Northwind sample database are stored in Orders and OrderDetails – the primary tables. DraftOrders and DraftOrderDetails tables will be created in order to store draft orders.

A custom action in DraftOrders controller will copy the draft order and order details to the primary tables, and delete the draft data rows.

Adding the DraftOrders and DraftOrderDetails Tables

Start SQL Server Management Studio. In the Object Explorer window, right-click on Databases / Northwind node, and press New Query.

Paste the following script into the query window:

create table dbo.DraftOrders(
    OrderID int IDENTITY(1,1) not null,
    CustomerID nchar(5) null,
    EmployeeID int null,
    OrderDate datetime null,
    RequiredDate datetime null,
    ShippedDate datetime null,
    ShipVia int null,
    Freight money null,
    ShipName nvarchar(40) null,
    ShipAddress nvarchar(60) null,
    ShipCity nvarchar(15) null,
    ShipRegion nvarchar(15) null,
    ShipPostalCode nvarchar(10) null,
    ShipCountry nvarchar(15) null,
    PRIMARY KEY (OrderID)
)
go

alter table dbo.DraftOrders add foreign key(CustomerID)
references dbo.Customers (CustomerID)
go

alter table dbo.DraftOrders  add foreign key(EmployeeID)
references dbo.Employees (EmployeeID)
go

alter table dbo.DraftOrders  add foreign key(ShipVia)
references dbo.Shippers (ShipperID)
go

create table dbo.DraftOrderDetails(
    OrderID int,
    ProductID int,
    UnitPrice money default (0),
    Quantity smallint default (1),
    Discount real default (0),
    primary key (OrderID, ProductID)
)
go

alter table dbo.DraftOrderDetails add foreign key (OrderID)
references dbo.DraftOrders (OrderID)
go

alter table dbo.DraftOrderDetails add foreign key (ProductID)
references dbo.Products (ProductID)
go

This script will create DraftOrders and DraftOrderDetails tables with the same columns as the primary Orders and OrderDetails tables. It also recreates the relationships with lookup tables – Customers, Employees, Shippers, and Products.

Run the script by pressing Execute on the toolbar.

Creating Draft Order Form

Follow the Order Form Sample tutorial to create a draft order form. Make sure to use DraftOrders and DraftOrderDetails instead of Orders and OrderDetails when implementing the form.

Creating “Submit Order” Action

The next step is to create an action that will move the draft order and draft order details into the original Orders and OrderDetails tables.

In the Project Designer, switch to the Controllers tab. Right-click on DraftOrders / Actions / ag2 (Form) node, and press New Action.

Assign the following values:

Press OK to save. Drop a100 – Custom, SubmitOrder | Submit Order node to the left side of the first action in ag2 to place it first in the group.

Handling the Action

Right-click on DraftOrders / Business Rules node, and press New Business Rule.

Assign these values:

In the Script property, enter the following:

begin transaction;

begin try
    -- move submitted order from DraftOrders to Orders
    insert into Orders (CustomerID, EmployeeID, OrderDate, 
                        RequiredDate, ShippedDate, ShipVia, 
                        Freight, ShipName, ShipAddress, 
                        ShipCity, ShipRegion, ShipPostalCode, 
                        ShipCountry)
    select CustomerID, EmployeeID, OrderDate, RequiredDate, 
            ShippedDate, ShipVia, Freight, ShipName, 
            ShipAddress, ShipCity, ShipRegion, ShipPostalCode, 
            ShipCountry
    from DraftOrders 
    where OrderID = @OrderID;

    -- find ID of committed order
    declare @NewOrderID int;
    select @NewOrderID = @@IDENTITY;

    -- move submitted order details from DraftOrderDetails to "Order Details"
    insert into "Order Details" (OrderID, ProductID, UnitPrice,
                                Quantity, Discount)
    select @NewOrderID, ProductID, UnitPrice,
            Quantity, Discount
    from DraftOrderDetails
    where OrderID = @OrderID;

    -- delete draft order and order details
    delete from DraftOrderDetails
    where OrderID = @OrderID;

    delete from DraftOrders
    where OrderID = @OrderID;

    commit transaction;

    -- refresh the page
    set @Result_NavigateUrl = 'OrderForm.aspx'
end try
begin catch
    rollback transaction;
    -- display error message
    declare @Error as nvarchar(500);
    select @Error = error_message();
    set @Result_ShowMessage = 'Order has not been submitted. ' + @Error;
end catch

Press OK to save.

Try testing the action – it will properly move the draft order and details into the Orders and OrderDetails tables. If any errors occur, the transaction will be rolled back and an error message will be displayed to the end user at the top of the web page.

A dedicated “Status” field in a database table is a simple and easy to implement method of separating “draft” and “committed” data. For example, orders stored in a database will be explicitly marked with a status of “Committed” if no changes are allowed to them. Orders still being composed will be marked with a status of “Draft”. The application must ignore draft data and have it visible only on the order entry page.

Adding the “Status” Column

Start SQL Server Management Studio. In the Object Explorer, right-click on Databases / Northwind and press New Query.

Paste in the following script to add the table column and mark all existing orders as “Committed”.

alter table Orders
add Status nvarchar(50) default 'Draft'
go

update Orders
set Status = 'Committed'
go

On the toolbar, press Execute to run the query.

Controlling Display of Draft Orders

Start the web application generator. Select the project name and click Settings. Press Business Logic Layer and enable shared business rules. Click Finish and regenerate the project.

Start the Project Designer. In the Project Explorer, switch to the Controllers tab. Right-click on Orders controller node, and press Edit Handler in Visual Studio.

The shared business rule file will open in Visual Studio. Replace the file with the following code:

C#:

using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using MyCompany.Data;

namespace MyCompany.Rules
{
    public partial class SharedBusinessRules : MyCompany.Data.BusinessRules
    {
        
        public SharedBusinessRules()
        {
        }

        protected override void EnumerateDynamicAccessControlRules(string controllerName)
        {
            if (Context.Request.UrlReferrer != null)
            {
                if (Context.Request.UrlReferrer.ToString().ToLower().Contains("orderform.aspx"))
                    RegisterAccessControlRule("OrderID", 
                        "select OrderID from Orders where Status = 'Draft'", 
                        AccessPermission.Allow);
                else
                    RegisterAccessControlRule("OrderID", 
                        "select OrderID from Orders where Status = 'Committed'", 
                        AccessPermission.Allow);
            }
        }
    }
}

Visual Basic:

Imports MyCompany.Data
Imports System
Imports System.Collections.Generic
Imports System.Data
Imports System.Linq

Namespace MyCompany.Rules

    Partial Public Class SharedBusinessRules
        Inherits MyCompany.Data.BusinessRules

        Public Sub New()
            MyBase.New()
        End Sub

        Protected Overrides Sub EnumerateDynamicAccessControlRules(controllerName As String)
            If Context.Request.UrlReferrer <> Nothing Then
                If Context.Request.UrlReferrer.ToString().ToLower().Contains("orderform.aspx") Then
                    RegisterAccessControlRule("OrderID",
                                            "select OrderID from Orders where Status = 'Draft'",
                                            AccessPermission.Allow)
                Else
                    RegisterAccessControlRule("OrderID",
                                            "select OrderID from Orders where Status = 'Committed'",
                                            AccessPermission.Allow)
                End If
            End If
        End Sub
    End Class
End Namespace

The implementation will conditionally register a dynamic access control rule that will apply to a view of any data controller with an OrderID data field. If the user is interacting with an application page ~/Pages/OrderForm.aspx, then only data that matches orders with a status of “Draft” is allowed. Otherwise, only data that matches orders with a status of “Committed” is included in the returned data set.

Adding “Submit Order” Action

In the Project Explorer, right-click on Orders / Actions / ag2 (Form) node, and press New Action.

Assign the following values:

Press OK to save the action. Drop Orders / Actions / ag2 (Form) / a101 – Custom, SubmitOrder | Submit Order node on the left side of a100 – Report | Order Report to place it first.

Adding Business Rule

Right-click on Orders / Business Rules node, and press New Business Rule.

Assign these values:

update Orders
set Status = 'Committed'
where OrderID = @OrderID

set @Result_NavigateUrl = 'OrderForm.aspx'

The business rule will set Status column of the selected order to “Committed” and refresh the page loaded in the web browser. Press OK to save.

Testing the Results

On the toolbar, press Browse. Navigate to the Order Form page. Create a new order and return to the grid. Note that only a single draft order is listed.

Navigate to the Orders page. Note that the all of the orders are displayed except for the draft order.

The draft order will also not be visible in any data controllers based on database views if they relate to orders. For example, page Reports | Order Subtotals will not display the new order. The dynamic access control rule explained above filters the order out.

Go back to the Order Form page, and select the draft order. Click on the “Submit Order” button.

The browser will refresh the page and display an empty list of orders.

The order will now be displayed on Orders page.

It will also be displayed on Order Subtotals page that can be found under the Reports option in the application navigation menu.