14.02.2009

Web Services

Web Services are means for integrating systems based on XML messaging. According to its official description by W3C, a web service is a software system designed to support interoperable interaction among computers over a network. Web Services are currently the preferred method for implementing systems that communicate with each other. 

A web service uses XML based messaging. Therefore, unlike earlier integration methods, the communicating systems need not be aware of each others' implementation details and do not have to be concerned with platform compatibility. For example, an application developed using Java and running on a Unix system, and another application developed using .NET and running on a Windows platform, may communicate using XML communication standards, while remaining independent of their operating environments. This is the most significant advantage of a web service. 

XML web services communicate using a protocol named SOAP (Simple Object Access Protocol). This is a web service communications standard. Thanks to SOAP, web services provide simple, message-based communications.




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Figure 1 - Software Development Process
 

Using a definition language named WSDL (Web Service Description Language), web services supply a definition of the service which they provide. Using the UDDI (Universal Description, Discovery and Integration) registration service, organizations are able to search for the services they require, and allow their own services to be discovered by others.

 

The Significance of Web Services for ERP

Organizations should be able to communicate with other organizations during the purchasing or supply chain management processes. Similarly, they should be able to communicate with business partners and automate their direct interactions with customers. 

Today, most organizations have to communicate with at least one system owned by an external entity corresponding to the interaction they execute for that process. Naturally, it will be preferable to choose a standards-based platform that also provides benefits during the implementation phase. The prevalent communication platforms used today are EDI and web services. 

It is possible to implement communication with diverse systems over EDI. However, the EDI based communication model is costly, both in terms of up-front development as well as later operating costs. For these reasons, an easier method that allows communication between systems has been sought. Web services is the most convenient method for an ERP system to communicate with other systems. 

Thanks to web services, an ERP system can be easily integrated with the information systems of a different organization, as well as be integrated with systems of different departments from within the same organization. Due to the loosely coupled communications infrastructure provided by web services, multiple systems can communicate with each other, independent of their platforms. 

With best wishes until we meet again in a future article.