Re: [xsl] FW: [Sedna-discussion] Strange issue when declaring default element namespace

Subject: Re: [xsl] FW: [Sedna-discussion] Strange issue when declaring default element namespace
From: Andrew Welch <andrew.j.welch@xxxxxxxxx>
Date: Wed, 29 Jun 2011 22:51:41 +0100
If you are talking about how changing the default namespace in xquery
changes the namespace used in the xpath, then yes that's how xquery
works.  It's a massive pain because there is no
xpath-default-namespace and its not possible to bind a prefix to the
empty default namespace.

The common example for this is creating xhtml from xml in no
namespace.  The typical work arounds are:

- move the xpaths into variables outside of the default namespace
change, then construct the result, so instead of:

<foo xmlns="123">{/path/to/whatever}</foo>

do:

let $elem := /path/to/whatever
return
 <foo xmlns="123">{$elem}</foo>

- or create the output in no namespace, then create the namespaced
output as the very last step (using the xquery equivalent of an
identity transform)
- use wildcards in your xpaths (which lets face it is convenient, but
we know its wrong)

Or best of all, if your xmldb supports it, use XSLT.




On 29 June 2011 22:26, Robby Pelssers <robby.pelssers@xxxxxxxxx> wrote:
> Hi all,
>
> I wanted to verify that my problem discussed in below thread is actually not
a bug but supposed to work like that.  Can someone confirm below findings?  I
think this question applies to several mailinglists (xquery/ xslt/ sedna).
>
> Thx in advance,
> Robby Pelssers
>
>
> -----Oorspronkelijk bericht-----
> Van: Robby Pelssers [mailto:Robby.Pelssers@xxxxxxx]
> Verzonden: wo 29-6-2011 23:13
> Aan: Robby Pelssers
> Onderwerp: FW: [Sedna-discussion] Strange issue when declaring default
element namespace
>
>
>
> From: Ivan Shcheklein [mailto:shcheklein@xxxxxxxxx]
> Sent: Wednesday, June 29, 2011 11:11 PM
> To: Robby Pelssers
> Cc: sedna-discussion@xxxxxxxxxxxxxxxxxxxxx; Ivan Lagunov
> Subject: Re: [Sedna-discussion] Strange issue when declaring default element
namespace
>
> Yes, as far as I understand. To be sure I've tested it on several
databases/engines. I'm 100% sure that prolog declaration influences names in
XPath. But I didn't know that xmlns attribute overrides locally value of the
default element namespace as well.
>
> You are welcome to ask this question on any other XQuery/XSLT forum. Let us
know results.
>
> Hi Ivan,
>
> Is this supposed to work this way?  Just to summarize by giving a small
example.
>
>
> (1)    I have a collection of documents  of schema A in XML DB
>
> (2)    I want to generate  documents of schema B having some specific
namespace
>
> Does xquery not provide this option without having to use 'ugly' [my
personal opinion] workarounds?  Actually I would expect that 'declaring a
default element namespace' was only targeting the output (elements) and not
the input (elements) but my assumption could be wrong.
>
> I will also share these findings on the XSLT mailing list just to be sure.
>
> Thx for your fast follow-up on my issues so far.
>
> To be continued,
> Robby Pelssers
>
>
>
> From: Ivan Shcheklein
[mailto:shcheklein@xxxxxxxxx<mailto:shcheklein@xxxxxxxxx>]
> Sent: Wednesday, June 29, 2011 10:57 PM
>
> To: Robby Pelssers
> Cc:
sedna-discussion@xxxxxxxxxxxxxxxxxxxxx<mailto:sedna-discussion@xxxxxxxxxxxxxx
rge.net>; Ivan Lagunov
> Subject: Re: [Sedna-discussion] Strange issue when declaring default element
namespace
>
> Robby,
>
> I was not correct. xmlns overrides default element namespace value for
everything inside the constructor expression. In this case it's just the same
as "declare default element" prolog declaration.
>
> The only way I see is to use wildcards:
>
> import module namespace demoboards= "http://www.nxp.com/demoboards";;
> let $results := demoboards:filterByName(demoboards:getDemoboards(), 'adc0')
> return <results  xmlns="http://www.nxp.com";>{ for $result in $results return
<id>{$result/*:DemoboardInformation/*:Name/text()}</id>} </results>
>
> Ivan Shcheklein,
> Sedna Team
>
> Hi Ivan,
>
> I have sent the testdata to your gmail account for protection of the data.
 I actually tested adding the namespace directly on the element a few days
ago. But that didn't work so that's why I was trying the approach setting the
namespace through the xmldb API.
>
> We are using release 3.4 of Sedna just to be sure and the latest (1.2.4)
Sedna xmldb api from Charles Foster.
>
> Kind regards,
> Robby
>
> From: Ivan Shcheklein
[mailto:shcheklein@xxxxxxxxx<mailto:shcheklein@xxxxxxxxx>]
> Sent: Wednesday, June 29, 2011 8:30 PM
>
> To: Robby Pelssers
> Cc:
sedna-discussion@xxxxxxxxxxxxxxxxxxxxx<mailto:sedna-discussion@xxxxxxxxxxxxxx
rge.net>; Ivan Lagunov
> Subject: Re: [Sedna-discussion] Strange issue when declaring default element
namespace
>
> Ok, can you send some sample data and demoboards:filterByName(),
demoboards:getDemoboards() to reproduce this?
> On Wed, Jun 29, 2011 at 9:31 PM, Robby Pelssers
<Robby.Pelssers@xxxxxxx<mailto:Robby.Pelssers@xxxxxxx>> wrote:
> Hi Ivan,
>
> I just tried the following queries and still expect we are dealing with a
bug.
>
> import module namespace demoboards= "http://www.nxp.com/demoboards";;
> let $results := demoboards:filterByName(demoboards:getDemoboards(), 'adc0')
> return <results>{ for $result in $results return
<id>{$result/DemoboardInformation/Name/text()}</id>} </results>
>
> <results>
>  <id>ADC0801S040</id>
>  <id>ADC0804S030</id>
>  <id>ADC0804S040</id>
>  <id>ADC0804S050</id>
>  <id>ADC0808S125</id>
>  <id>ADC0808S250</id>
> </results>
>
> import module namespace demoboards= "http://www.nxp.com/demoboards";;
> let $results := demoboards:filterByName(demoboards:getDemoboards(), 'adc0')
> return <results  xmlns="http://www.nxp.com";>{ for $result in $results return
<id>{$result/DemoboardInformation/Name/text()}</id>} </results>
>
> <results xmlns="http://www.nxp.com";>
>  <id/>
>  <id/>
>  <id/>
>  <id/>
>  <id/>
>  <id/>
> </results>
>
> From: Ivan Shcheklein
[mailto:shcheklein@xxxxxxxxx<mailto:shcheklein@xxxxxxxxx>]
> Sent: Wednesday, June 29, 2011 7:19 PM
> To: Robby Pelssers
> Cc:
sedna-discussion@xxxxxxxxxxxxxxxxxxxxx<mailto:sedna-discussion@xxxxxxxxxxxxxx
rge.net>; Ivan Lagunov
> Subject: Re: [Sedna-discussion] Strange issue when declaring default element
namespace
>
> Hi Robby,
>
> The default element namespace declaration influences all unprefixed element
names. Including all names in XPath: $result/DemoboardInformation/Name/text()
(I mean DemoboardInformation and Name). If your data doesn't contain
namespaces at all it's better for you to declare default element namespace
right within the constructor:
>
> ...
> return <result xmlns="....">{...}</result>
> ...
>
> Ivan Shcheklein,
> Sedna Team
>
> Hi all,
>
> I am a bit puzzled why the query below returns:
>
> import module namespace demoboards= "http://www.nxp.com/demoboards";;
> let $results := demoboards:filterByName(demoboards:getDemoboards(), 'adc0')
> return <results>{ for $result in $results return
<id>{$result/DemoboardInformation/Name/text()}</id>} </results>
>
> <results>
>  <id>ADC0801S040</id>
>  <id>ADC0804S030</id>
>  <id>ADC0804S040</id>
>  <id>ADC0804S050</id>
>  <id>ADC0808S125</id>
>  <id>ADC0808S250</id>
> </results>
>
> If I add a default element namespace I still find the same amount of results
but all expressions are evaluated 'empty'
>
> import module namespace demoboards= "http://www.nxp.com/demoboards";;
> declare default element namespace "http://www.nxp.com";;
> let $results := demoboards:filterByName(demoboards:getDemoboards(), 'adc0')
> return <results>{ for $result in $results return
<id>{$result/DemoboardInformation/Name/text()}</id>} </results>
>
> <results xmlns="http://www.nxp.com";>
>  <id/>
>  <id/>
>  <id/>
>  <id/>
>  <id/>
>  <id/>
> </results>
>
> Am I misunderstanding something here or is this a bug in Sedna?
>
> Kind regards,
> Robby Pelssers
>
>
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--
Andrew Welch
http://andrewjwelch.com

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