98 The XML Files: Develo pment of XML/XSL A pplications Using WebSp here Studio
5.6 Web services support
XML and its associated family of standards play a central role in Web services by
providing a data interchange format that is independent of b oth programming
languages and operating systems. This section gives an overview of the support
provided by the Application Developer for XML-based Web services. For detailed
information about the development of XML Web services using Websphere
Studio Application Developer, please refer to Chapter 9. Please note that we
assume you already have a background about Web services.
To start developing your Web service, you will need to create a Web project in
your work space to contain the Web service. To implement your XML Web
service, the Application Developer provides you with the two very important
wizards to use.

Web Service DADX group configuration wizard

DAD extension (DADX) is an extension of the DB2 XML Extender document
access definition (DAD) file. A DADX document specifies how to create a Web
service using a set of operations that are define d by SQL statements or DAD
files. DAD files are files that describe the mapping between XML do cuments
elements and DB2 database columns. They are used by t he DB2 XML Extender,
which supports XML-based operations that store or retrieve XML documents to
and from DB2 database.
The Web services DADX group configuration wizard enables you to create a
DADX group. The DADX group created with this wizard is used to store DADX
documents. A DADX group contains connection (JDBC and JNDI) and other
information that is shared between DADX files.
Once you have created a DADX group, you can import DADX files and then start
the Web services wizard to create a Web service from a DADX file. A DADX file
is created using the XML from SQL query wizard.

Web service wizard

This wizard is used for creating Web services. It is cable of generating several
types of Web services. The focus of this book is only on DADX Web services.
Using the wizard, you can specify to generate a Web service proxy class. A Web
service proxy class makes it very easy to invoke a Web service. You just
instantiate the class and invoke the desired method on it.
Moreover, the wizard gives you the ability to generate and invoke a sample
application. The sample application is a small Web application, which enables
you to invoke the different methods of the Web service, and to view the results.