In this chapter we saw that there are tremendous advantages to using XML as the means of representing data that is shared between applications. We have also learned the following:
XML allows applications to evolve more easily. It provides the flexibility to enhance data structures to handle the changes that businesses need to make. In doing so, XML allows you to upgrade your systems incrementally and continuously.
XML provides a richer data model than relational databases and includes standards-based transformation grammars such as XSLT and XQuery.
XML also supports best practices that enable resilient data access in evolving XML schema. This is accomplished through the proper use of XPath and XML data access APIs. It is expected that tools and methodologies will be developed that automate and validate these best practices.
XML alone won't accommodate all the data exchange requirements of an enterprise that is dealing with legacy systems and partner interactions. With the help of intelligent content-based routing and targeted transformation services, ESB lays the groundwork for a generic data exchange architecture and the basis for more sophisticated business process management.