Native XML databases - Making Sense of NoSQL - page 110

and efficient to update XML documents. The larger the XML documents are, the
more critical it is to use the update function.
The W3C standardized XQuery updates in 2011. The other XQuery specification
that was released by the W3C in 2011 was the full-text extension, which we'll cover next.

5.2.6 XQuery full-text search standards

Native XML systems are used to store both business documents like sales orders and
invoices, and written documents like articles or books. Because native XML databases
are used to store large amounts of textual information, there's a strong demand for
high-quality search of these documents. Fortunately, the W3C has also created
XQuery-based standards for full-text search.
XQuery supports a search extension module that standardizes how search func-
tions are performed on a full-text database (a database that contains a complete text
of the topics, journals, magazines, newspapers, or other kinds of textual material in a
collection). This extension to the XQuery language specifies how search queries
should be specified in terms of XQuery functions
Search standards are important because they allow your XQuery search applica-
tions to be portable to multiple native XML databases. In addition, using standards in
full-text search code and processes allows staff to port their knowledge from one XML
database to another, reducing training and application development time.
The specification also provides guidelines on advanced functions such as Boolean
and nearness operations. The key difference is that with native XML databases, each
node can be considered its own document and have its own indexing rules. This
allows you to set up rules to weight matches in the title of a document above matches
in the body of a document. We'll review the concepts of search and weighting in
greater detail in chapter 7.
We've now reviewed how to build a web application using a native XML database.
You've seen how data is loaded, transformed, updated, and searched using XQuery
and XQuery extensions. Now let's take a look at other standards used in native XML
databases that allow you to build portable applications.

5.3 Using XML standards within native XML databases

XML standards allow you to reuse your knowledge and code as you move from one
native XML database to another. They also allow you to keep your NoSQL applications
portable across different implementations of NoSQL databases and prevent vendor
lock-in. Standards make it easier to learn a new NoSQL system, which helps you and
your team get your products to market faster. If you're already familiar with an API or
data standard, your application development using that standard will be faster with
each subsequent project.
Let's begin with an overview of some of the XML standards we've discussed and
add some new standards to the mix. Table 5.1 lists the key standards used in native
XML systems, the organization associated with the standard, and a description of how
the standard is used.