XQuery/eXist Crib sheet

Imports and Declarations

XQuery declaration

xquery version "1.0";

import a module

import module namespace geo="http://www.cems.uwe.ac.uk/exist/coord" at "coord.xqm";

Base eXist namespace

  declare namespace exist = "http://exist.sourceforge.net/NS/exist"; 

Standard eXist modules

Optional in an XQuery script but required in a module in 1.2 but not in 1.3

 import module namespace xmldb = "http://exist-db.org/xquery/xmldb";
 import module namespace util = "http://exist-db.org/xquery/util";
 import module namespace request = "http://exist-db.org/xquery/request";
 import module namespace response = "http://exist-db.org/xquery/response";
 import module namespace session = "http://exist-db.org/xquery/session";
 import module namespace transform = "http://exist-db.org/xquery/transform";
 import module namespace text = "http://exist-db.org/xquery/text";
 import module namespace system = "http://exist-db.org/xquery/system";

declare a namespace

 declare namespace tx="http://www.transxchange.org.uk/";

declare a default element namespace

declare default element namespace "http://www.w3.org/1999/xhtml";

Be VERY careful if you use a default namespace. This means that everything that does not have a namespace prefix will automatically be serialized into this namespace. It also PREVENTS you from using the null namespace unless you specifically declare it as xmlns="". Note that you do NOT associate a prefix with the default namespace.

declare a default function namespace

declare default function namespace "http://www.transxchange.org.uk/";

declare a java binding namespace

declare namespace math="java:java.lang.Math";

Note that the java binding is disabled by default due to security issues. Math functions can now be invoked via the maths extension module.

Serialization Options

output XML document

This is the default, but can be declared explictly:

declare option exist:serialize "method=xml media-type=text/xml omit-xml-declaration=no indent=yes";

output SVG document

declare option exist:serialize "method=svg media-type=application/svg xml omit-xml-declaration=no indent=yes";

output XHTML document

declare option exist:serialize "method=xhtml media-type=text/html omit-xml-declaration=no indent=yes 
        doctype-public=-//W3C//DTD XHTML 1.0 Transitional//EN
        doctype-system=http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd";

If your code contains a lot of XML fragments that are in the NULL namespace (xmlns="") then there is a method of automatically converting everything in the null namespace to automatically get put into the XHTML namespace.

declare option exist:serialize "method=xhtml enforce-xhtml=yes";

output HTML4 document

declare option exist:serialize "method=xhtml media-type=text/html omit-xml-declaration=no indent=yes 
        doctype-public=-//W3C//DTD HTML 4.01 Transitional//EN
        doctype-system=http://www.w3.org/TR/loose.dtd";

output HTML5 document

declare option exist:serialize "method=html5 media-type=text/html omit-xml-declaration=yes indent=yes";

output HTML document with no doctype

declare option exist:serialize "method=html media-type=text/html omit-xml-declaration=yes indent=yes";

output XHTML document with no doctype

declare option exist:serialize "method=xhtml media-type=text/html omit-xml-declaration=yes indent=yes";

output plain text document with no doctype

declare option exist:serialize "method=text media-type=text/plain omit-xml-declaration=yes";

output kml document

declare option exist:serialize  "method=xhtml media-type=application/vnd.google-earth.kml xml highlight-matches=none";

output XForms document

declare option exist:serialize "method=xhtml media-type=text/xml indent=yes";

Modules and Functions

module header

module namespace c="http://www.cems.uwe.ac.uk/exist/coord";

function declaration

• in the default namespace in an XQuery script

declare function local:times($tt, $dt) {
  if (exists($dt))
  then local:times(($tt, $tt[last()]  $dt[1]), remove($dt,1))
  else $tt
};

• in the namespace of a module

module namespace time = 'http://www.cems.uwe.ac.uk/fold/time';
declare function time:times($tt, $dt) {
  if (exists($dt))
  then time:times(($tt, $tt[last()]  $dt[1]), remove($dt,1))
  else $tt
};

declare variable

declare variable $pi as xs:double := 3.14159265;

in a module with namespace prefix fxx:

declare variable $fxx:file := doc('/db/me/file.xml');

embedded CSS stylesheet

  <style language="text/css">
  <![CDATA[
    .good {background-color: green;}
    .bad {background-color:red;}
  ]]>
  </style>

Get HTTP POST URL Parameters

To get two URL parameters from an HTTP POST

   http://localhost:8080/exist/rest/db/my-collection/my-xquery.xq?color=blue&shape=circle

Add the following:

  let $my-color := request:get-parameter('color', 'red')
  let $my-shape := request:get-parameter('shape', '')

If no color parameter is supplied a default color of "red" will be used.

Get HTTP POST Data

To get all the XML data from an HTTP POST

  let $my-data := request:get-data()

Extend the Output Size Limit

By default the output size in 10,000 bytes. You can extend this by adding the following

declare option exist:output-size-limit "new-size";

For example to triple the size limit of the output use the following line:

declare option exist:output-size-limit "30000";