Once words are written, as an author I consider them to be fixed. Even typos should be acknowledged as being corrected and not silently “improve” the original text. Rather than editing what has been said, more words can cover the same ground with the hope of doing so more completely or usefully.
I am starting my XQuery series of posts with the view of being more systematic, including references to at least one popular XQuery book, along with my progress through a series of uses of XQuery.
You are going to need an XQuery engine for all but this first post to be meaningful so let’s cover getting that setup first.
There are any number of GUI interface tools that I will mention over time but for now, let’s start with Saxon.
Download Saxon, unzip the file and you can choose to put saxon9he.jar in your Java classpath (if set) or you can invoke it with the -cp (path to saxon9he.jar), as in java -cp (path to saxon9he.jar) net.sf.saxon.Query -q:query-file.
Classpaths are a mixed blessing at best but who wants to keep typing -cp (your path to saxon9he.jar) net.sf.saxon.Query -q: all the time?
What I have found very useful (Ubuntu system) is to create a short shell script that I can invoke from the command line, thus:
#!/bin/bash
java -cp /home/patrick/saxon/saxon9he.jar net.sf.saxon.Query -q:$1
Which after creating that file, which I very imaginatively named “runsaxon.sh,” I used chmod 755 to make it executable.
When I want to run Saxon at the command line, in the same directory with “runsaxon.sh” I type:
./runsaxon.sh ex-5.4.xq > ex-5.4.html
It is a lot easier and not subject to my fat-fingering of the keyboard.
The “>” sign is a pipe in Linux that redirects the output to a file, in this case, ex-5.4.html.
The source of ex-5.4.xq (and its data file) is: XQuery, 2nd Edition by Patricia Walmsley. Highly recommended.
Patricia has put all of her examples online, XQuery Examples. Please pass that along with a link to her book if you use her examples.
If you have ten minutes, take a look at: Learn XQuery in 10 Minutes: An XQuery Tutorial *UPDATED* by Dr. Michael Kay. Michael Kay is also the author of Saxon.
By this point you should be well on your way to having a working XQuery engine and tomorrow we will start exploring the structure of the congressional roll call vote documents.