Native XML databases - Making Sense of NoSQL - page 123

Although XML is frequently associated with slow processing speeds, this often has
more to do with a specific implementation of an XML parser or a slow virtual machine.
It has little to do with how native XML systems work. The generation of XML directly
from a compressed tree storage structure is usually on par with any other format such
as CSV or JSON .
All native XML databases start with the cache-friendly document store pattern and
gain from the elimination of middle-tier, object-translation layers. They then leverage
the power of standards to gain both portability and reuse of XQuery function librar-
ies. The use of standard metaphors like data folders to manage document collections
and simple path expressions in queries make native XML databases easy to set up and
administer for nontechnical users. This combination of features has yet to appear in
other NoSQL systems, since standardization is only critical as third-party software
developers look for application portability.
Despite the W3C 's work on extending XQuery for updates and full-text search,
there are still areas that lack standardization. Although native XML databases allow
you to create custom indexes for things like geolocation, RDF data, and graphs, there
are still few standards in these areas, making porting applications between native XML
databases more difficult than it needs to be. New work by the W3C , EXPath develop-
ers, and other researchers may mitigate these problems in the future. If these stan-
dards continue to be developed, XQuery-based document stores may become a more
robust platform for NoSQL developers.
The cache-friendliness of documents and the parallel nature of the FLWOR state-
ment make native XML databases inherently more scalable than SQL systems. In the
next chapter, we'll focus on the some of the techniques NoSQL systems use when
managing large datasets.

5.9 Further reading

 eXist-db. http://exist-db.org/.
 EXPath. http://expath.org .
 JSONiq. “The JSON Query Language.” http://www.jsoniq.org .
 MarkLogic. http://www.marklogic.com.
 “Metcalfe's Law.” Wikipedia. http://mng.bz/XqMT .
 “Network effect.” Wikipedia. http://mng.bz/7dIQ .
 Oracle. “Oracle Berkeley DB XML & XQuery.” http://mng.bz/6w3z .
 TEI . “ TEI : Text Encoding Initiative.” http://www.tei-c.org .
 W3C . “EXPath Community Group.” http://mng.bz/O3j8 .
 W3C . “ XML Query Use Cases.” http://mng.bz/h25P .
 W3C. “XML Schema Part 2: Datatypes Second Edition.” http://mng.bz/F8Gx .
 W3C. “XQuery and XPath Full Text 1.0.” http://mng.bz/Bd9E .
 W3C. “XQuery implementations.” http://mng.bz/49rG .
 W3C. “XQuery Update Facility 1.0.” http://mng.bz/SN6T .
 XSPARQL . http://xsparql.deri.org .