PowerExchange for Web Services is a web service consumer that exchanges data with a web service provider. It integrates with PowerCenter to read data from a web service source and write data to a web service target. It also lets you use a web service to transform data during a session.

For example, you want to use PowerCenter to read loan request data from a database and run credit checks on the data, passing only those loan requests that pass the credit check to a target. Although you might not have the capability in-house to perform credit checks, you can process the loan request data in the mapping using an external web service. When you locate a web service that performs credit check operations, you can import it and use it as a Web Services Consumer transformation in a PowerCenter mapping. The PowerCenter Integration Service can connect to the web service during a session, so the web service can perform credit checks on the loan request data before the PowerCenter Integration Service writes the data to a target.

A web service is a collection of web service operations that you can access over an intranet or the Internet. Web service operations are programs that return data. When you access a web service, you request that the web service perform an operation and return data. A web service can contain many web service operations. For example, a web service that provides stock quotes might have a web service operation that returns the highest stock price of the day, a web service operation that returns the lowest stock price of the day, and a web service operation that returns the closing price for the day.

Web service operations contain input and output messages. Input and output messages are XML-formatted messages. They specify how to structure a request for a web service.

Web service access involves providers and consumers. A web service provider refers to the server that hosts the web service. A web service consumer refers to the client that requests a web service. PowerExchange for Web Services accesses web services as a web service consumer.

The web service you access can be remote or local. Someone at another organization can create and publish the web service, or someone at your organization can create and publish it.

Before you can read data from a web service, write data to a web service, or transform data using a web service, you must import a web service operation. You import a web service operation from a Web Services Description Language (WSDL) file. WSDL files describe web services and web service operations. PowerExchange for Web Services uses the information in the WSDL file to access a web service operation.

PowerExchange for Web Services uses the Simple Object Access Protocol (SOAP) to exchange information with the web services provider and request web services. SOAP is a protocol for exchanging information between computers. It specifies how to encode XML data so that programs on different operating systems can pass information to each other. Web services hosts contain WSDL files and web services.