eXtc is a fully functional Native XML Database. Native XML Databases are particularly useful for applications such as Document Management. Read Ronald Bourret's detailed paper on XML and Databases.
If you want to find out more about why you should consider Native XML Databases, and the kinds of applications that suit them, Ronald has recently completed publication of a series of papers on use cases for Native XML Databses (M/Gateway Developments were contributors to his research). The articles are highly recommended:Part 1
eXtc will allow you to develop any of the classes of application described in these papers.