Oracle XML DB is a feature of the Oracle Database. It provides a high-performance, native XML storage and retrieval technology. It fully absorbs the W3C XML data model into the Oracle Database, and provides new standard access methods for navigating and querying XML. With Oracle XML DB, you get all the advantages of relational database technology plus the advantages of XML.
In Oracle Database 11g Release 2, new capabilities, such as XMLIndex structured component and partitioning, as well as numerous enhancements of Oracle XML DBare introduced to dramatically improve its performance, scalability, XML schema management, and XML information lifecycle management.
The XML DB Sample Code Library contains downloadable code samples to help you understand how to develop applications that take advantage of Oracle's XML technology and the Oracle XML DB Repository. Installation instructions for the code samples can be found here
Oracle has a very active research organization (Oracle Labs) that is charged to 'Identify, explore, and transfer new technologies that have the potential to substantially improve Oracle's business'. One part of the organization is the External Research Office (ERO). The ERO is charged to ' ... invest in research collaborations that fit Oracle's long-term strategic goals. These collaborations are between university researchers and engineers/researchers throughout Oracle's various organizations'. The ERO webpage lists numerous current and past collaborations. Oracle provides funds and direct interactions with highly experienced developers.