Integrating Access 2003 with XML Web Services

Prior to its release, there was widespread speculation that most Microsoft Office System 2003 members would include native support for XML Web services. As mentioned in Chapter 1's "Support for XML Web Services" section, this didn't happen; only InfoPath 2003 has out-of-the-box support for retrieving and updating SQL Server and Jet data with XML Web services. The initial reaction of most Access power users and developers to this omission is likely to be "So what?" When this book was written, XML Web services were in the "early adopter" stage. Major players in the RDBMS market IBM, Microsoft, and, to a lesser degree, Sun Microsystems and Oracle have invested many millions of dollars to integrate XML Web services with their data-related development tools. Microsoft emphasizes support for XML Web services as a key incentive for migrating to Windows Server 2003 and Visual Studio .NET.

Note

Microsoft uses the term XML Web services to differentiate the subject of this chapter from conventional Web services, such as search services, electronic commerce applications, portals, and the like. Most other development tool and application server vendors, such as BEA Systems, Borland, IBM, Oracle, and Sun Microsystems drop the XML prefix. The XML prefix applies to all instances of the term Web service(s) in this chapter.

The benefits of Web services assure their ultimate adoption as the lingua franca of interoperable software components of distributed applications. Unlike Microsoft's Component Object Model (COM and COM+), Web services are platform- and operating system-agnostic. Conventional Web services use HTTP (TCP port 80) or Secure HTTP (HTTPS, TCP port 443) as the transport protocol for XML text messages. Few firewalls block text content on these ports, so you can connect to public Web services over the Internet. HTTPS currently is the most common method for securing confidential messages by encrypting the human-readable XML content.

A Microsoft Office Web Services Toolkit enables your Access applications to connect to and utilize most basic Web services written in any programming language and running on Linux, Unix, or Windows servers. The key to Web services' interoperability is adherence to a set of public standards and specifications developed by the World Wide Web Consortium (W3C), the Organization for the Advancement of Structured Information Standards (OASIS), and the Web Services Interoperability (WS-I) Organization.

Note

WS-I doesn't purport to be an official standards organization. WS-I's charter is to establish a common set of specifications for implementing existing Web service standards. WS-I published its first recommendation, Basic Profile Version 1.0, in early 2003. WS-I also provides tools for testing Web service conformance to the recommendations. Links to all WS-I specifications are at http://www.ws-i.org.

The Office XP Web Services Toolkit 2.0, which Microsoft released in July 2002, was the current version when this book was published. You can expect Microsoft to release updated versions periodically. The Toolkit adds the Web Service References Tool (WSR) 2.0 to the Visual Basic Editor's Tools menu. WSR automatically generates almost all the VBA code you need to consume simple and complex Web services. The Toolkit also includes useful documentation and sample Web service consumer applications.

This advanced chapter shows you how to take advantage of WSR with typical public Web services and describes a simple approach to delivering rowsets from SQL Server stored procedures as Web services. The chapter also includes instructions for installing and using Microsoft's .NET WebService Studio, which is an exceptionally useful tool for learning Web service technology and message structure.