They are XML databases, a way to store, search, and retrieve all that mission-critical business data that is finding expression in XML format.

The XMLType data type obscures much of the complexity of storing and querying XML data, allowing admins to manipulate the data using familiar SQL tools and concepts.

Because XML data lends itself to a hierarchical structure rather than a relational structure, it may be difficult to store XML data in traditional relational database systems.

IBM released the initial open beta of an update to DB2 that will give users the ability to natively store unstructured data in an XML repository that's separate from conventional relational data.