Converting Relational to Hierarchical Data Tutorial

Relational data is typically saved as tables or views in a relational database. Hierarchical data is typically saved as XML data, and sometimes as tables or views in a hierarchical database such as IMS.

This tutorial uses three of the tables shipped with TDV from the Examples project (customers, orders, and orderdetails) to produce an XML document result.

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Adding the Views to Convert

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Adding the Loops and Filters Used to Iterate and Select Data

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Completing the Links Between Loop and out

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Adding Loop2 to the Model

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Adding Loop3 to the Model

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Adding Links to Direct Data Flow

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Executing the Transform

Adding the Views to Convert

Add three of the tables shipped with TDV from the Examples project (customers, orders, and orderdetails).

To convert relational to XML data

Open Studio.

In the Studio resource tree, select Shared.

Right-click and select New Transformation.

Select Any-Any Transformation and click Next.

Type TBL2XML in the Transformation Name field.

Click Finish.

The Transformation Editor opens with the Model tab displayed.

From the Studio resource tree, expand Shared/examples.

Expand Shared/examples/ds_orders.

Select the following views and drag them from the resource tree onto the Transformation Editor Model tab:

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customers

—

orders

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orderdetails

10.

Save your transform.

Adding the Loops and Filters Used to Iterate and Select Data

This example makes use of programmatic loops to iterate through and select the data to be transformed.

To add loops and filters

11.

Select the Loop Link Mode. Alternatively hold SHIFT key while creating a link (Shift+Minus) icon at the top of the editor.

12.

Select the operation handle next to the result column that is listed in customers and drag the line to out.

13.

Save the transform.

14.

Delete the connection between loop and out.

15.

On the out container, select the operation handle next to customers and right-click.

16.

Select Delete “customers”.

17.

Click out to select it.

18.

Right-click out and select Add Parameter.

19.

Select Browse.

20.

Browse to XMLdefinitionSet.

21.

Select Type in the Show drop down list on the right.

22.

Select Customers from that list.

23.

Click OK.

By default, the XML hierarchy is collapsed.

24.

Click the arrow next to foo:customer, then foo:orders, and foo:orderitems to expand the hierarchy.

25.

Click the Assign Link Mode. Alternatively hold CTRL key while creating a link (CTRL+Minus) icon at the top of the editor.

26.

From loop, click in the operation handle next to customers and drag the line to foo:customer.

27.

Save your transform.

Completing the Links Between Loop and out

To complete loop links

28.

Click the Assign Link Mode icon at the top of the editor.

29.

Link CustomerID to foo:customerID.

30.

Link CompanyName to foo:CustomerName.

31.

Save your transform.

Adding Loop2 to the Model

To add loop2

32.

Select the Loop Link Mode.

33.

Click in the operation handle next to the result column of the orders table and connect it to the foo:orders column of out.

34.

Double-click loop2.

35.

In the field, type the following:

CusID = orders/CustomerID

36.

Click Close.

37.

Save your transform.

Adding Loop3 to the Model

To add loop3

38.

Select the Loop Link Mode.

39.

Link orderdetails result to foo:orderItems.

40.

Double-click loop3.

41.

In the field, type the following:

OrdID = orderdetails/OrderID

42.

Save your transform.

Adding Links to Direct Data Flow

Linking data on certain columns helps direct the flow of data and help select the data for transformation.

To add links

43.

Open your transform.

44.

Validate and or create links between the following From and to columns.

From Operator	From Column	To Operator	To Column
loop	customers	out	out.foo.customer
	CustomerID	out	out.foo.customerID
	CompanyName	out	foo.customerName
	CustomerID	Loop2	CusID
loop2	orders	out	out.foo.orders [ ]
	OrderID	out	out.foo.orderID
	OrderID	loop3	loop3.OrdID
loop3	orderdetails	out	foo.orderitems [ ]
loop3	OrderDetailID	out	foo.orderitemID

45.

Save your transform.

Executing the Transform

When you execute a transform the convert relational data into XML structured hierarchical data, you can use the results to get an idea of what would be produced at runtime.

To execute the transform

46.

Execute your transform to review the generated XML code. (Click the execute button.)

47.

Click Details on the Results panel to view the Value window.

48.

Click OK to close the Value window when you have finished.

49.

Save and close your transform.