Web Services Q&A - December 2002/January 2003

Section A: Web Services and PowerBuilder

1. How can I determine which of my existing PowerBuilder objects could be called as Web services?
2. My PowerBuilder application needs to access a Web service that returns an XML document containing the results from a database query. How can I call the Web service from my PowerBuilder application and process the XML document response?

Section B: Web Services and EAServer

3. What are the steps for creating a WSDL file in EAServer?
4. Where can I find samples that demonstrate how to use Web services with EAServer?
5. What Web services security standards does EAServer support?

Section C: Web Services, ASE, and .Net

6. How can I use a Windows VB.Net client to consume a Web service written in Java accessing data from a Sybase database running on Linux server?

1. How can I determine which of my existing PowerBuilder objects could be called as Web services?

The EAServer Web Services Toolkit automatically supports PowerBuilder components whose method signatures contain CORBA C++ IDL datatypes, and/or arrays of those datatypes. In addition, the Web Services Toolkit allows you to create and utilize User-Defined data types. A list of the CORBA C++ IDL datatypes, and information about User-Defined types is provided in Chapter 7 of the Web Services Toolkit User's Guide.

2. My PowerBuilder application needs to access a Web service that returns an XML document containing the results from a database query. How can I call the Web service from my PowerBuilder application and process the XML document response?

The techniques for calling Web services from PowerBuilder, and for working with XML depend on the version of PowerBuilder you are using.

To call a Web service from PowerBuilder:

• In PowerBuilder 9, invoke the Web service directly. See WDSL in PowerBuilder 9.
• In PowerBuilder 8, utilize a third-party SOAP Client to invoke the Web service. See the " A PowerBuilder Client for Axis" section of http://www.sybase.com/detail?id=1020318 for an example.

Once you receive the response, utilize the XML data in the response as desired. For example, transform the XML into a different format, then import it into a DataStore object.

For PowerBuilder 9, see:

• XML Features in PowerBuilder 9
• Native XML Services in PowerBuilder 9
• DataWindows, XML & XSL-FO in PowerBuilder 9

For PowerBuilder 8, see:

• How to utilize XML technology with PowerBuilder 7 or 8
  

3. What are the steps for creating a WSDL file in EAServer?

The EAServer Web Services Toolkit provides a GUI to simplify and automate the creation of WSDL files and corresponding client proxies, and to publish the location of your WSDL documents to a UDDI registry on the Web.

Creating a WSDL document using the EAServer Web Services Toolkit GUI consists of a few simple steps:

a. Pick an EAServer component to use as a Web service
b. Specify the addresses where it can be accessed (protocol, port, host)
c. Pick which component methods you want listed as operations

Based on your choices, the Web Services Toolkit creates a WSDL file, along with the corresponding interface and implementations files.

See Chapter 3 in the EAServer Web Services Toolkit User Guide for more information, including step-by-step instructions.

4. Where can I find samples that demonstrate how to use Web services with EAServer?

There are numerous samples available to demonstrate different ways to utilize Web services with EAServer. Two sample applications are installed as part of the Web Services Toolkit:

• An application showing how to use the Sybase ClientProxy to construct and send SOAP requests to EAServer. For details and usage instructions, see Webservices\sample\Sample\demo.htm in your EAServer installation directory.
• An application that demonstrates how to use .NET with EAServer. The Web Services Toolkit User's Guide provides documentation for using the sample.

Additional samples are available on Sybase.com, including:

• Apache Axis - The Third Generation SOAP Implementation
• SOAP Development with PowerJ 4.0 and PowerBuilder 8.0
• JAXP: Coding for Parser and Transformer Independence

5. What Web services security standards does EAServer support?

The EAServer Web Services Toolkit relies on the EAServer security mechanisms to control access to the Web services it exposes. Enterprise-class Web services developed with EAServer inherit and leverage integrated advanced security capabilities including single sign-on, role-based access control, and Secure Business Objects (SBO) out of the box.

For more information on enterprise security in EAServer, see http://www.sybase.com/content/1020493/L02095_EAServer_Enterprise_Security_Brief.pdf

6. How can I use a Windows VB.Net client to consume a Web service written in Java accessing data from a Sybase database running on Linux server?

Deploy your Java component to EAServer, and use the Web Services Toolkit to expose the component as a Web service. The Java component can be pooled, and can utilize an EAServer connection cache for database access. As a result, you have the added benefit of scalability and performance in your application. The Web Services Toolkit supports .NET clients, and even includes a sample to help you get started. See Chapter 9 of the Web Services Toolkit User Guide.