Skip to Content
XQuery
book

XQuery

by Priscilla Walmsley
March 2007
Intermediate to advanced
512 pages
21h 15m
English
O'Reilly Media, Inc.
Content preview from XQuery

Chapter 9. Advanced Queries

Now that you are an expert on the syntax of XQuery expressions, let's look at some more-advanced queries. This chapter describes syntax and techniques for some commonly requested query capabilities. You may have these same requirements for your queries, but even if you don't, this chapter will show you some creative ways to apply XQuery syntax.

Copying Input Elements with Modifications

Often you will want to include elements from an input document, but with minor modifications. For example, you may wish to eliminate or add attributes, or change their names. However, the XQuery language does not have specific update capability, nor does it have any special functions or operators that perform these minor modifications. For example, there is no direct syntax that means "select all the product elements, but leave out their dept attributes."

The good news is that you can accomplish these modifications by "reconstructing" the elements. For example, you can write a query to construct a new product element and include all the children and attributes (except dept) of the original product element in the input document. Even better, you can write a user-defined function that uses computed constructors to handle these modifications in the general case. This section describes some common modifications and provides useful functions to handle these cases.

Note that these functions are intended to change the way elements and attributes appear in the results of a query, ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

XSLT

XSLT

Doug Tidwell
XPath and XPointer

XPath and XPointer

John Simpson
XQuery Kick Start

XQuery Kick Start

James McGovern, Per Bothner, Kurt Cagle, James Linn, Vaidyanathan Nagarajan

Publisher Resources

ISBN: 0596006349Errata