Recently, XQuery had a significant impact on other technologies. The new content management standards (JSR 170) uses a language inspired by XQuery. The Business Processing Language (BPEL) has integrated XQuery as one of the potential XML expression languages that can be invoked from BPEL programs. Finally, the SQL-XML standard defines a way to blend, mix, and match traditional relational queries with XML queries expressed in XQuery, a useful functionality to all applications that have to process relational data and XML data at the same time.

Several APIs are under development to enable applications written in various programming languages to invoke XQuery programs. Examples are XQJ (JSR 225) or the extensions of JDBC to invoke SQL-XML in the Java community.

In addition to the set of standards to be implemented this year, there's significant work being done in XML processing. There are two major areas that need attention.

The first extension to XQuery 1.0 will concern the ability to pose full-text queries and mix them with structured queries. The XQuery full-text extension allows complex full-text predicates ranging from simple string search to complex predicates constructed using operators such as negation, distance, ordering, or window filtering. The full-text search can be parameterized using traditional methods of full-text search like thesauri, diacritics, stemming, or language.

The XQuery working group has also proposed an extension of XQuery for XML update operations. XQuery 1.0 is a side-effect free language and doesn't allow the modificaiion of the input data. Such an update extension will let users insert new nodes in existing XML structures, delete fragments of XML trees, rename elements or attributes, or change their content in a declarative fashion.

Despite the work of the XQuery WG, missing functionalities remain. Among the most requested missing features are better support for analytics (group-by) and better support for continuous queries (windowing). Such functions are well supported in SQL and it's expected that XQuery will provide similar capabilities. Other possible extensions are better integration with XSLT, better integration with Web Services and the Semantic Web set of standards. A certain community of users would like to see XQuery extended to a full scripting language for XML.

XML isn't disappearing into the infrastructure, as some pundits predicted. It's become the infrastructure and everything else is disappearing into it. Yet, I believe, XML won't achieve its great potential unless we know how to process it in a declarative fashion. XQuery might be the answer to that question.