XQuery: omit namespaces for source documents containing no namespaces

Question

I want to use XQuery in order to map between two XML documents. Whereas the source document does not contain any namespace declaration, the target document requires a target namespace (must be the default namespace according to the system processing it). I understand that XQuery always requires a namespace (and everything within XQuery is in a namespace). However I would like so simplify my XQuery's XPath expressions and especially would like to omit namespaces wherever possible.

The following example illustrates the situation:

Source document

<?xml version="1.0" encoding="UTF-8"?>
<!-- note that this documents does not declare any namespace -->
<a>
    <b>
        <c>ABC</c>
    </b>
</a>

XQuery file

xquery version "1.0";

declare variable $doc := .;

let $abc := $doc/a/b/c
return
<foo xmlns="http://www.example.org">    
    <bar1>{$doc/a/b/c/text()}</bar1>    
    <bar2>{$doc/*:a/*:b/*:c/text()}</bar2>
    <bar3>{$abc/text()}</bar3>    
</foo>

This generates the following (Saxon-HE 9.5.1.3):

<?xml version="1.0" encoding="UTF-8"?>
<foo xmlns="http://www.example.org">
   <bar1/>
   <bar2>ABC</bar2>
   <bar3>ABC</bar3>
</foo>

Basically I would like to be able to construct elements as in the first rule (bar1), i. e. without using namespaces in XPath expressions. Unfortunately that does not seem to work. Instead I have to use a more laborious syntax as in the 2nd rule (bar2).

A workaround (well, rather a hack) would be to have variables declared before introducing the namespaces (see bar3), but I am sceptical if this is a good idea as a) it probably wouldn't scale for larger documents and b) it prevents from declaring the default element namespace "properly", i. e. as intended by XQuery via a separate declaration in the document header.

Does anyone have an idea how to achieve the desired behaviour? Thank you very much in advance!

Michael Kay Michael Kay · Accepted Answer · 2017-05-29T09:56:26

Unfortunately in XQuery the default namespace for names in XPath expressions is always the same as the default namespace for constructed elements.

One workaround is to use computed element constructors:

element Q{http://www.example.org}foo {    
    element Q{http://www.example.org}bar1 {$doc/a/b/c/text()}
}

I agree, it's not pretty.

XSLT 2.0 got this one right with separate default namespaces for input and output. I remember trying to convince the XQuery WG that this was needed, and failing.

XQuery: omit namespaces for source documents containing no namespaces

1 Answers