XQuery mines the rich seam of XML
data
XML has evolved to become the standard format for platform- and
system-independent data exchange. Ever more data sources are able to
export content in XML format, making it available to many other
XML-enabled databases and applications. Even leading vendors of
conventional relational database management systems such as IBM,
Oracle and Microsoft have seen fit to modify their products to support
XML data. However, it is not enough to be able to view this data. To
make the most of XML's remarkable potential, users must be able to
query, retrieve, edit and, above all, update information as they see
fit.
With the benefit of XQuery, an integrated query language based on
the recommendations of the W3C, native XML databases and database
management systems such as the one integrated in Tamino XML Server
from Software AG make it easy for users to edit and update XML data as
they please. However, complications arise when XML is used in
conjunction with data from other sources, for instance, relational
databases.
Now that XML is well on its way to becoming the universal standard
for data exchange in the age of the Internet and e-commerce, ever more
vendors are opting for XML as the enabler of unlimited data and
information transfer. A case in point is Microsoft and its .NET
Initiative. Despite the general consensus on XML's benefits, it takes
more than just the capability of incorporating and representing XML
data to enable true platform-independent data exchange.
Even if XML may be imported into the most diverse data management
applications, in most cases these lack a suitable query language that
allows users to target, retrieve, analyze and update specific
contents. Particularly the importance of updating should not be
underestimated. The only way users can tap into the full potential of
XML - for example, to access and use information no matter which type
of end device they happen to have at hand - is with the benefit of
these powerful features.
XML data may be formatted for any purpose
Now that XML has arrived, the vision of one digital world may
finally be realized. Users have long wished for a single format for
data storage and retrieval, as well as a means to label information
content so that it may be formatted in virtually any conceivable
layout. That can now be achieved by means of tags, which are special
formatting instructions embedded in documents, and document types,
which are determined by precise document type definitions.
With these features, all information archived in XML may be
formatted and employed for the most diverse purposes. Documents can be
sent to various appliances such as PCs or handheld computers with
different screen sizes for viewing purposes, or printed out as
hardcopy books, pamphlets or newsletters, to name just a few
applications.
Ever more relational databases offer XML as a data export
option
XML data and databases have a distinct advantage over relational
databases. Relational databases archive data in tabular structures,
which demands considerable resources for retrieval and processing. XML
databases make do with far less computing power. Many relational
database system providers are keen to exploit that advantage - witness
IBM, Oracle and Microsoft - so they are rolling out ever more products
that support export of relational database contents in XML
format.
This means that data stored in relational databases may be handled
much like that in native XML databases. Though this doesn't appease
relational databases' voracious appetite for computing performance,
nor does it speed up sluggish response and shorten the long wait for
information to be presented on screen, it does attest to the fact that
pure XML data is much easier to process than converted relational
data.
The XML view of relational data is a one-way street
Unfortunately, converting relational data to XML format is all give
and no take. A static rather than dynamic process, it enables data to
be viewed, but not edited or updated. A better solution would be if
relational databases were to support XML-enabled viewing and
publishing of database contents as a standard feature. Additional
advantages would follow if information from XML and relational
databases could be exchanged, processed and updated without
limitations via a single uniform query model.
A first step in this direction has been made, and it is called
XQuery. A standard sanctioned by the World Wide Web Consortium (W3C),
it extends XML with comprehensive query options. It also facilitates
database content updates, but unfortunately at this time only in
conjunction with XML Servers such as Tamino from Software AG.
Fast becoming the standard for XML queries, XQuery enables
effortless navigation within the hierarchic directory structure of XML
documents. Many tools based on XQuery are now available which enable
XML views of relational database contents. Again though, their
capabilities are limited to viewing information. Features that empower
users to edit and update databases are unavailable - at least for the
time being. Software AG has recently developed an XQuery test product
named QUIP, which is publicly available at the Tamino Developer
Community. Using QUIP, you can test how XQuery works.
A uniform query model for native XML and relational databases
will come
The tremendous revenue potential of e-commerce and e-business is
driving enterprise's demand for a query model common to native XML
databases and XML views of relational databases, and that demand is
sure to grow. A universal and jointly usable XML query language's time
will come. Users are clamoring for universal systems because they
realize that comprehensive data handling capabilities are critical to
gaining and maintaining the competitive edge in international markets.
The debate over a standard interface for data and communication was
settled some time ago, and it is becoming ever more evident that XML
came out on top.
Today's native XML databases protect tomorrow's
investments
This new universal query language will certainly evolve from
XQuery. The reasons for this are, for one, that XQuery has already
become a standard courtesy of the W3C's endorsement and, for the
other, almost all vendors of native XML databases have started to
implement the new XQuery standard into their products. Moreover, it is
quite conceivable that any future universal XML query language will be
enhanced with further features by the various makers of XML
products.
Software AG also integrates XQuery into the search engine of its
Tamino XML Server augmenting it with additional options such as text
searches using specific character strings, words and terms. This means
that enterprises will soon have a new universal query language at hand
that handles XML and relational database contents. They can opt for a
native XML database today and enjoy maximum investment protection for
tomorrow because all providers of native databases support the W3C's
specifications in their entirety.
Experience has shown that the industry is quick to implement the
W3C's draft specifications once they have been published, so it won't
take long for the eagerly awaited new universal query language to be
integrated into products.
|
