 | Level: Intermediate Keith Wells (wellsk@us.ibm.com), Advisory Software Engineer, IBM
Susan Malaika (malaika@us.ibm.com), Senior Technical Staff Member, IBM
Christian Pichler (cpichle@us.ibm.com), Data Server Solutions (Co-op), IBM
08 May 2008 Understand the end-to-end exchange of XML data from an XForms-based
browser to an IBM® DB2® database with full XML support. Learn how easy
it is to create XForms and have them communicate with a DB2 database, where XML data
can be stored, retrieved, or deleted. Learn, also, how to create the XForms that
access the DB2 pureXML through Universal Services.
Introduction
XML is being widely used as the medium to exchange messages between many software
systems due to its simplicity, readability, extensibility, and acceptance across
the IT industry. XML technology has been proven to be so successful that other
industries such as banking, insurance, healthcare, and retail are also developing
XML standards to make communication between systems easier, interoperable, and
less cumbersome.
The software industry is also improving the standards and tools to build
applications to create and move XML messages and documents across
multi-disciplinary applications.
This article presents you with technologies for quick creation of pureXML
databases for XML messages, Universal Web Services to interact with these pureXML
databases, and XForms which can be used to interrogate and visualize data from the
stored XML messages to a user in a client-based browser.
Goal
The goal of this article is to help you create an XML-based application quickly
— making XML standards work for you by exchanging XML documents from an
XForms-implementing browser to a DB2 pureXML database that stores XML data
natively.
Setting the scene
This section provides the necessary background you need in order to follow the
approach presented throughout this article.
Figure 1. Setting the scene
IRS e-File 1120 message
The Internal Revenue Service (IRS) is part of the United States Department of
the Treasury that supports individuals and companies to report their income,
credits, and other information. Therefore, the IRS defined e-file messages based
on the Extensible Markup Language (XML). E-file messages are an electronic
alternative to filing paper reports. In particular, the IRS e-File 1120 message is
designed for corporations to determine the tax liability for the corporation.
XForms
XForms is a W3C XML standard for presenting and collecting form-based data. It is
tightly integrated with XML with a strong separation between presentation controls
and data. See the Resources section of this article for
more developerWorks articles and other resources on XForms.
XML Forms Generator
The XML Forms Generator tool is an IBM alphaWorks package (Eclipse plug-in)
intended to jump-start XForms development. It produces valid and functional forms
containing XForms markup embedded within an XHTML document. The input to form
generation may be an XML message (optionally) backed by an XML schema or a WSDL
document. Response processing templates and combination request/response forms
also may be generated from a WSDL document.
Any document the XML Forms Generator produces may serve as a starting point for
further form, layout, and styling customizations. An extension point provides
opportunities for post-processing during generation of a form.
DB2 pureXML
IBM DB2 supports storing, managing, and querying entire XML documents or document
fragments. Application developers can now store XML data directly inside a DB2
database and reap the benefits of transactions, advanced data resiliency, secure
access, and the ability to search large amounts of XML data using XQuery.
DB2 pureXML provides simple, efficient access to XML with the same levels of
security, integrity, and resiliency taken for granted with relational data.
DB2 pureXML industry bundles
The industry bundle sample packages and demos contain vertical industry samples
of XML documents, links to relevant XML schemas, and sample code to help database
administrators, software developers, and architects in vertical industry
businesses get started with DB2 9.x pureXML features. If you need more information
or are interested in downloading these samples, please refer to the
Resources section. In this article, you will be working
with the IRS e-File 1120 pureXML industry bundle.
Universal Services
The Universal Services enable someone to set up a fixed set of database
operations on top of a pureXML database within a short period of time. These
database operations are furthermore exposed as Web services operations. The Web
services operations exposed allow the user to insert, update, delete, and query
XML data stored in a pureXML column of a DB2 database.
Universal Services are based on the Data Web Services mechanism, which allows you
to expose database operations, stored procedures, and user-defined functions as
Web services.
Scenario
This section of the article provides an overview of the scenario setup and
describes the parts of the scenario that need to be set up in advance. As shown in
Figure 2, the approach followed in this article consists of
three layers — data, Universal Services, and user interaction.
Figure 2 furthermore illustrates one of the advantages of the
approach shown here: XML data end-to-end, which means that data is stored
as XML, exchanged as XML, and presented to the user as XML.
As illustrated in Figure 1, the same IRS e-File 1120 XML
message is stored, exchanged, and used as the basis for display through an XForm.
Figure 2. Overview architecture
The purpose of each of these layers is as follows:
-
Data: The data layer represents a DB2 pureXML database containing a table
that has a column of type XML. The pureXML column enables the database to store
XML messages in a native format. The data stored in this database is the data
you're going to design the XForms for, as part of this article — the IRS
1120 e-File message. A convenient and easy way to set up sample databases for a
great variety of different XML-based industry standards is to use the DB2
pureXML Industry Bundles. The industry bundle used in this scenario is the one
created for the IRS e-File Form 1120.
-
Universal Services: The Universal Services layer enables the column of
type XML in the DB2 pureXML database in the Data layer to be accessed and
modified through Web service operations.
-
User interaction: The user interaction layer is the main purpose of this
article. It represents user interaction through XForms. These XForms allow the
retrieval, modification, and update of the data in the DB2 pureXML database. The
XForms access the data in the pureXML database through the Universal Services.
The setup of a DB2 pureXML database to store IRS e-File 1120 XML messages
and the setup of the Universal Services are described in the article
"Universal
Services for pureXML using Data Web Services."
 |
XForms
This section describes the basic steps to create XForms capable of end-to-end XML
exchange with a DB2 pureXML database. These steps are:
Step 1: Obtain WSDL file
The first step in designing the XForm is to generate the WSDL file for the
Universal Services by accessing the URL
http://localhost:8080/UniversalServices/wsdl, as described in the article
"Universal
Services for pureXML using Data Web Services."
Depending on your local system setup, hostname, port, or both may need to be
adapted. Save this file locally, and import it or copy and paste it as a .wsdl
file in an Eclipse project. In this article, the WSDL file is saved with the file
name universalservices.wsdl.
Step 2: Build XForms that interact with
Universal Services
You can generate the interaction (request and response) XForms and the
corresponding XML files to communicate with the Universal Web Services for a
pureXML solution using the XML Forms Generator (XFG) tool. The XML Forms Generator
Eclipse plug-in processes the Universal Services Web service descriptions that
were imported into the Eclipse project in the previous step.
- Select the universalservices.wsdl file, right-click on the WSDL file,
and choose the Generate Request/Response XHTML/XForm wizard from the XML
Forms Generator menu item (see Figure 3 below).
Figure 3. Generate
Request/Response XHTML/XForm from WSDL file
- From the wizard, select the Web service operations for the XForms you are
producing.
The XML Forms Generator wizard produces two files for each Web service operation
selected. One operation is getXMLDocumentByKey. The two
files produced by the wizard are getXMLDocumentByKey.xhtml and
getXMLDocumentByKey.xml. As you can see in Listing 1, below,
getXMLDocumentByKey.xml is a SOAP message that will be submitted in your IRS
e-File 1120 application:
Listing 1. Generated SOAP message
<?xml version="1.0" encoding="ASCII"?>
<soapenv:Envelope
soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soapenv:Header
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
<soapenv:Body
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<UniversalServices:getXMLDocumentByKey
xmlns:UniversalServices="UniversalServices">
<id xsi:type="xsd:string" />
</UniversalServices:getXMLDocumentByKey>
</soapenv:Body>
</soapenv:Envelope>
|
The other file generated, namely getXMLDocumentByKey.xhml is the interaction
XForm. If you were to render the generated interaction XForms in a browser, it
would look like Figure 4:
Figure 4. Rendered view of the
getXMLDocumentByKey Web service
You'll use parts of this interaction XForm, as illustrated in Listing 2, later.
Listing 2. XForms submission for Universal Services
<xforms:submission id="submit_model_Envelope"
action="http://localhost:8080/UniversalServices/services/UniversalServices"
method="post"
mediatype="text/xml"
replace="instance">
<xforms:toggle ev:event="xforms-submit-done" case="response"/>
</xforms:submission>
|
Step 3: Build XForms that display IRS e-File
Form 1120 XML messages
Import an IRS 1120 e-File XML message from the industry bundle (as described in
the article
"Universal
Services for pureXML using Data Web Services")
into your Eclipse project. Generate the display XForms with the XML Forms
Generator "Generate XHTML/XForms" wizard. The wizard produces an XHTML/XForms file
(the display XForms) using the data from the IRS 1120 e-File XML message. Figure 5
shows what the display XForms looks like after it was generated, customized, and
rendered in Firefox:
Figure 5. Rendered view of the IRS
e-File 1120 XML sample message
Step 4: Merge the XForms (from Steps 2 and 3)
to create an interactive end-to-end XML application
By merging the interaction and display XForms (see
Listing
3), you can put together an application that
queries the pureXML DB2 database for IRS e-File 1120 XML messages, selects
different messages, and displays the messages using XForms presentation controls.
To merge the interaction and display XForms, complete the following steps:
- Ensure that all namespaces are set properly.
- Establish the XForms model created during Step 3 to represent the data being
returned.
- Modify the relative XPath references to account for accessing the data from a
SOAP envelope.
Listing 3. Basic structure of our combined XForms
<xforms:switch>
<xforms:case id="request" selected="true">
<!-- Start Page for XForms demo -->
<!-- Create Trigger to get all IRS e-File 1120 messages -->
</xforms:case>
<xforms:case id="primaryKeys">
<!-- Select from list of documents -->
<!-- Copy/Paste from the XForms generated for the
getXMLDocumentByKey web service -->
</xforms:case>
<xforms:case id="request_xforms">
<!-- Form and data of an IRS e-File 1120 message -->
<!-- Copy/Paste from the XForms generated from the
IRS e-File 1120 XML Document -->
</xforms:case>
</xforms:switch>
|
The Download section of this article provides a complete
example that illustrates how to merge the interaction and display XForms.
Conclusion
Following the instructions in the article
"Universal Services for pureXML using Data
Web Services,"
you created a database and installed the Web services to interact with the
database through the Universal Services. By following the instructions in this
article, you built XForms that utilize the Web service interfaces to retrieve,
store, and delete XML documents from a DB2 database.
This solution, from XForms to DB2 pureXML, provides end-to-end XML data exchange
between XForms-capable browsers and a database (see Figure 1
and Figure 2). Integrating and submitting XML data from XForms
through an SOA interface to a database means there are fewer steps between the
user and the database, less server processing, and quicker development time to
retrieve and process XML data from a XForms-capable browser.
Download | Description | Name | Size | Download method |
|---|
| XForms example | xforms_example.zip | 4.9KB | HTTP |
|---|
Resources Learn
- "Universal Services for pureXML using Data
Web Services"
(developerWorks, May 2008): Get started with configuring, testing, and modifying
the Universal Services, a simple but fixed set of database operations that allow
the querying and modification of XML data.
-
W3C XForms: Find links to the
official XForms specification and a variety of XForms rendering options.
-
W3C site: Find out more about XHTML, Cascading
Style Sheets (CSS), XML, XML Events, XPath, and other related standards.
-
Internal Revenue Service - United States Department of the Treasury:
Find information on the Internal Revenue Service (IRS), forms to file different
reports and electronic versions of these forms, called e-File forms.
-
"IBM
Data Studio: Get Started with Data Web Services"
(developerWorks, November 2007): Get a very detailed and simple introduction to
developing your first Data Web Service.
-
"Data Web Services: Build
Web
Services the new way to access IBM database servers"
(developerWorks, December 2007): Create and customize a Data Web Service. Useful
theoretical background on Data Web Services is provided, which includes an
architectural overview on Data Web Services. The article addresses different
aspects of Data Web Services, such as security.
-
"Expose DB2 9 pureXML using WebSphere
Integration Developer"
(developerWorks, September 2007): Build a client to access the Universal Services.
Follow step-by-step instructions on how to build, test, and deploy a mediation
module that can store well-formed XML documents in a DB2 XML column using a
WebSphere Integration Developer module.
-
developerWorks Information Management zone:
Learn more about Information Management. Find technical documentation, how-to
articles, education, downloads, product information, and more.
-
developerWorks XForms
space:
Find information on XForms, and share you experiences with other XForms users.
- Stay current with
developerWorks technical events and webcasts.
-
Technology bookstore:
Browse for books on these and other technical topics.
Get products and technologies
-
Industry Formats and Services with pureXML:
Download a great variety of examples, for free! Each example illustrates how to
work with XML-based Industry Formats and pureXML. The examples show how to
register an XML Schema, how to perform validation of XML instance documents, how
to query XML data using XQuery or SQL/XML and much more.
-
DB2 Express-C:
Download the free version of DB2, which includes the core functionality as the
other Data Servers, such as the pureXML technology. DB2 Express-C is free to
develop, deploy, and distribute.
-
Mozilla XForms: Render your
standards-compliant forms in Mozilla Firefox using this plug-in.
-
FormsPlayer: Render XForms on Internet
Explorer using this plug-in.
-
XML Forms Generator: Create
functional, standards-compliant forms with a click of the mouse using this
Eclipse-based tool from alphaWorks.
-
Visual XForms Designer: Check
out links to installation instructions, prerequisites, and the forum for this
standards-based, easy-to-use Eclipse plug-in enabling the rapid development of
documents with XForms mark-up using a visual user interface.
-
Compound XML Document Toolkit:
Explore other open-standard XML markups, including Scalable Vector Graphics (SVG),
MathML, VoiceXML, and Synchronized Multimedia Integration Language (SMIL).
- Build your next
development project with
IBM trial software,
available for download directly from developerWorks.
Discuss
About the authors | 
| | Keith Wells is the technical and team lead for XForms development in IBM Emerging Standards in RTP, N.C. Currently, Mr. Wells is a member of the W3C Forms Working Group and is exploring opportunities with XForms, emerging software standards, industry standards and other XML-based technologies. |
| 
| | Susan Malaika is a senior technical staff member in IBM's Information Management Group (part of IBM Software Group). Her specialties include XML, the Web, and databases. She has developed standards that support data for grid environments at the Global Grid Forum. She has also co-authored a book on the Web and published articles on
transaction processing and XML. She is a member of the IBM Academy of Technology. |
| 
| | Christian Pichler is a co-op from the Technical University of Vienna in Austria, where he is working on his thesis for a double Master's degree in Computer Engineering and Computer Science with a focus on healthcare. For IBM, Christian is working on technologies for storing XML in DB2, and accessing it through Web services, feeds, and XForms. He is specializing in XML standards for healthcare. |
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