As XML becomes an increasingly important data interchange format, it makes sense to look at new ways of storing information directly in XML and using XML-based tools for data query and manipulation. However, what those tools will look like is still very much up in the air.
A native XML database market is emerging to tackle this need. XML databases such as Ixiasoft Inc.s TextML Server, Software AGs Tamino and XYZFind Corp.s XYZFind Server allow data to be submitted in XML format, provide XML-based query languages and return data in XML format. However, eWeek Labs tests show that, just because program data is in XML format, a native XML database is not necessarily the right place to store it.
Generally speaking, XML databases just arent technically strong enough to compete with relational databases—XML databases lack numerous administrative, interoperability, programmability and manageability benefits provided by the big relational databases.
Lack of clear standards is also a problem in the XML database space. The XPath query syntax unfortunately has no support for grouping, sorting or summarizing data, and the much richer XQuery query language is still in draft form. And even when XQuery is formalized, its likely that it wont support updates, inserts or deletions.
For early adopters of XML databases, this means increased costs until these issues are sorted out because the XML databases available now all use vendor-proprietary query languages and programming interfaces.