Walkthrough: Using Database and .NET Facts

Article
02/02/2021

This walkthrough provides step-by-step procedures for using the Business Rule Composer to create a policy that uses database and .NET facts.

Prerequisites

You must set the value of the StaticSupport registry key to 1 or 2 before performing the walkthrough. This allows the policy to invoke the static methods of a .NET class without requiring the client to assert an instance of the class. For more information, see Invoking Static Members of a Class.

Overview of This Walkthrough

This walkthrough contains five procedures, as described in the following table.

Procedure title	Procedure description
To create the TestDB database and the PO table	Provides step-by-step instructions for creating the TestDB database and the PO table.
To create the POUtility component	Provides step-by-step instructions for creating the POUtility component.
To create the ProcessPurchaseOrderDbNet business policy	Provides step-by-step instructions for creating the ProcessPurchaseOrderDbNet policy.
To test the ProcessPurchaseOrderDbNet policy by using the Business Rule Composer	Provides step-by-step instructions for using the Business Rule Composer to test the ProcessPurchaseOrderDbNet policy.
To test the ProcessPurchaseOrderDbNet policy by using the Policy.Execute method	Provides step-by-step instructions for testing the ProcessPurchaseOrderDbNet policy by using the Policy.Execute method.

To create the TestDB database and the PO table

Open SQL Server Management Studio.
Verify the server name and authentication, and then click Connect.
In the Object Explorer window on the left, right-click the computer name, and then click New Query.

Copy the following SQL statements to the query window:

CREATE DATABASE [TestDB]  
GO  

Use TestDB  
CREATE TABLE [dbo].[PO]([PONumber] [nvarchar](50) NOT NULL,  
[Quantity] [int] NOT NULL,  
[Status] [nchar](10) NULL  
CONSTRAINT [PK_PO] PRIMARY KEY CLUSTERED ([PONumber] ASC))   
GO  

INSERT INTO PO VALUES ('PO1', 400, NULL)  
INSERT INTO PO VALUES ('PO2', 700, NULL)  
GO

Press F5 to execute the SQL query.
In the Object Explorer window, expand the computer name, expand Databases, and then verify that TestDB exists.
Expand TestDB, expand Tables, and then verify that dbo.PO exists.
Right-click dbo.PO, and then click Open Table to verify that the following data exists in the table.

PONumber Quantity Status

PO1 400 NULL

PO2 700 NULL

PONumber	Quantity	Status
PO1	400	NULL
PO2	700	NULL

To create the POUtility component

Start Microsoft Visual Studio.
In Visual Studio, on the File menu, point to New, and then click Project.

In the New Project dialog box, do the following:

Use this	To do this
Project types	Click Visual C#.
Templates	Click Class Library.
Name	Type POUtilityLib.
Location	Specify C:\BRE-Walkthroughs as the location.
Solution Name	Type POUtilitySol.
Create directory for solution	Select this check box to create a directory for the solution files.

Click OK. The POUtilityLib project should appear in Solution Explorer. If you do not see Solution Explorer, click Solution Explorer on the View menu.
In the Properties window, change the name of the file, Class1.cs, to POUtility.cs.
Add a public constructor to the class as shown in the following code:
```
public POUtility()  
{  
}  
```
Add a static method named GetMaxAllowed to the POUtility class as shown in the following code:
```
public static int GetMaxAllowed()  
{  
return 500;  
}   
```
Start Visual Studio Command Prompt.
Change the directory to C:\BRE-Walkthroughs\POUtilitySol, and then execute the following command:

Sn -k POUtility.snk
In Visual Studio, in Solution Explorer, expand Properties, and then double-click AssemblyInfo.cs.

Add the following statement to the AssemblyInfo.cs file at the end:

[assembly: AssemblyKeyFile(@"C:\BRE-Walkthroughs\POUtilitySol\POUtility.snk")]

In the Solution Explorer window, right-click POUtilityLib, and then click Build.
At the Visual Studio Command Prompt, change the directory to C:\BRE-Walkthroughs\POUtilitySol\POUtilityLib\Bin\Debug, and then execute the following command to register the POUtility component with the GAC (global assembly cache). If you do not have the command prompt open, follow step 8 to open it.

Gacutil -i POUtilityLib.dll

To create the ProcessPurchaseOrderDbNet business policy

On the Start menu, open Business Rule Composer. If you have the Business Rule Composer already open, press F5 to refresh it.

Note

On a system that supports User Account Control (UAC), you may need to run the tool with Administrative privileges. To do this, right-click the application, and then select Run as administrator.
In the Facts Explorer window, click Databases.
Right-click Servers, and then click Browse.
Verify the server and authentication information, and then click OK.
Expand TestDB, and then expand PO.
In the Facts Explorer window, click .NET Classes.
Right-click .NETAssemblies, and then click Browse.
Select POUtility, and then click OK.
Expand Class1.
In the Policy Explorer window, right-click Policies, and then click Add New Policy.
Change the name of the policy from Policy1 to ProcessPurchaseOrderDbNet and then press ENTER. You can also change the name of the policy in the Properties window.
Right-click Version 1.0, and then click AddNewRule.
Change the name of the rule from Rule1 to ApprovalRule and then press ENTER. You can also change the name of the rule in the Properties window.
In the IF pane (top) on the right, right-click Conditions, click Predicates, and then click LessThanEqual.
In the Facts Explorer window, click Databases.
Drag the Quantity node from the Facts Explorer window to argument1 in the IF pane.
In the Facts Explorer window, click .NET Classes.
Drag GetMaxAllowed node from the Facts Explorer window to argument2 in the IF pane.
In the Facts Explorer window, click Databases.
Drag the Status node from the Facts Explorer window to the THEN pane at the bottom right of the Business Rule Composer.
In the THEN pane, click <Enter a value> and then type Approved.
In the Facts Explorer window, right-click Version 1.0 in ProcessPurchaseOrderDbNet, and then click AddNewRule.
Change the name of the rule from Rule1 to DeniedRule and then press ENTER. You can also change the name of the rule in the Properties window.
In the IF pane (top) on the right, right-click Conditions, click Predicates, and then click GreaterThan.
In the Facts Explorer window, click Databases.
Drag the Quantity node from the Facts Explorer window to argument1 in the IF pane.
In the Facts Explorer window, click .NET Classes.
Drag the GetMaxAllowed node from the Facts Explorer window to argument2 in the IF pane.
In the Facts Explorer window, click Databases.
Drag the Status node from the Facts Explorer window to the THEN pane at the bottom right of the Business Rule Composer.
In the THEN pane, click <Enter a value> and then type Denied.
In the Policy Explorer window, right-click Version 1.0 (not saved), and then click Save.

To test the ProcessPurchaseOrderDbNet policy by using the Business Rule Composer

On the Start menu, open Business Rule Composer. If you have the Business Rule Composer already open, press F5 to refresh it.
In the Policy Explorer window, expand Policies, expand ProcessPurchaseOrderDbNet, right-click Version 1.0, and then click Test Policy.
Click TestDB:PO (Data Connection), and then click Add Instance.
In the Connect to SQL Server dialog box, verify the server name and authentication information, and then click OK.
In the Select Binding dialog box, expand TestDB, click PO, and then click OK.
Click Test.
In the Output window, verify that both the ApprovalRule and the DeniedRule are fired.
In SQL Server Management Studio, right-click dbo.PO, and then click Open Table.
Verify that the value of the Status field is set to Approved for the first record.
Verify that the value of the Status field is set to Denied for the second record.

Note

If you still see the value of the Status field as NULL, right-click the list containing the data, and then click Execute SQL, which refreshes the view.
Keep SQL Server Management Studio open.

To test the ProcessPurchaseOrderDbNet policy by using the Policy.Execute method

Start Microsoft Visual Studio.
In Visual Studio, on the File menu, point to New, and then click Project.

In the New Project dialog box, do the following:

Use this	To do this
Project types	Click Visual C#.
Templates	Click Console Application.
Name	Type TestProcessPODbNet.
Location	Specify C:\BRE-Walkthroughs as the location.
Solution Name	Type TestProcessPODbNetSol.
Create directory for solution	Select this check box to create a directory for the solution files.

Click OK. The TestProcessPODbNet project should appear in Solution Explorer. If you do not see Solution Explorer, click Solution Explorer on the View menu.
In Solution Explorer, right-click References, and then click Add Reference.
Click Browse, browse to \Program Files\Common Files\Microsoft BizTalk, and then double-click Microsoft.RuleEngine.dll.

Add the following code to the top of the Program.cs file after the existing using statements:

//To use the SQLConnection class  
using System.Data.SqlClient;  

//To use the Policy and DataConnection classes  
using Microsoft.RuleEngine;

Add the following code to the Main function to create and open a SQLConnection object:

SqlConnection cn = new SqlConnection("Data Source=(local);Initial Catalog=TestDB;Integrated Security=SSPI");  
cn.Open();

Add the following code to the Main function at the end to create a DataConnection object based on the SQLConnection object you created in the previous step:
```
DataConnection dc = new DataConnection("TestDB", "PO", cn);  
```
Add the following code to the Main function at the end to create a Policy object and execute the policy:
```
Policy policy = new Policy("ProcessPurchaseOrderDbNet");  
policy.Execute(dc);  
```
Add the following code to the Main function at the end to update the database:
```
dc.Update();  
```
Add the following code to the Main function at the end to close the connection to the database:
```
cn.Close();  
```
Add a try-catch block to catch any exception generated in the Main method.

Verify that the complete code for the Main function is as shown in the following code:

try  
{  
SqlConnection cn = new SqlConnection("Data Source=(local);Initial Catalog=TestDB;Integrated Security=SSPI");  
cn.Open();  
DataConnection dc = new DataConnection("TestDB", "PO", cn);  
Policy policy = new Policy("ProcessPurchaseOrderDbNet");  
policy.Execute(dc);  
dc.Update();  
cn.Close();  
}  
catch (Exception ex)  
{  
Console.WriteLine(ex.Message);  
}

On the Build menu, click Build TestProcessPODbNet.
In the Business Rule Composer, expand Policies, expand ProcessPurchaseOrderDbNet, right-click Version 1.0, and then click Publish.
Right-click Version 1.0 - Published, and then click Deploy.
In SQL Server Management Studio, set the value of the Status field to NULL for both the PO records.
In Visual Studio, Press CTRL+F5 to execute the TestProcessPODbNet application.
Press any key to close the command prompt window.
In SQL Server Management Studio, right-click the table with PO records, and then click Execute SQL.
Verify that the value of the Status field is set to Approved for the first record.
Verify that the value of the Status field is set to Denied for the second record.

Comments

If a policy uses the non-static methods of a .NET class, you need to use a fact creator component that asserts an instance of the .NET class to test the policy by using the Business Rule Composer.
It is very important to remember that the Business Rule Composer creates an instance of the DataConnection object and asserts it into the working memory of the rule engine automatically for you. However, when you invoke the policy from a client (BizTalk or non-BizTalk) application, the DataConnection object is not created automatically for you. The client should create a DataConnection object and pass it as a parameter or fact to the rule engine to execute the policy.
You can use the DebugTrackingInterceptor class to track the policy execution details. The following sample code shows how to create an instance of the DebugTrackingInterceptor class, and use it when executing the policy:
```
DebugTrackingInterceptor dti = new DebugTrackingInterceptor("c:\\Trace.txt");  
policy.Execute(dc, dti);  
```

You can use the SqlTransaction class to update the database from the ProcessPODbNet policy in a transactional manner. The following code shows how to begin a transaction, pass the transaction as a parameter to the DataConnection object, and commit the database changes. For more information, see Transaction Support.

SqlConnection cn = new SqlConnection("Data Source=(local);Initial Catalog=TestDB;Integrated Security=SSPI");  
cn.Open();  
//Begin the transaction  
SqlTransaction  tn = cn.BeginTransaction();  
//Pass the transaction object to the DataConnection constructor  
DataConnection dc = new DataConnection("TestDB", "PO", cn, tn);  
Policy policy = new Policy("ProcessPurchaseOrderDbNet");  
DebugTrackingInterceptor dti = new DebugTrackingInterceptor("c:\\Trace.txt");  
policy.Execute(dc, dti);  
dc.Update();  
//Commit the database transaction  
tn.Commit();  
cn.Close();

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