[xquery-talk] How to invert the hierarchy of an xml?

[Geert Josten]

-----Oorspronkelijk bericht-----
Van: talk-bounces at x-query.com [mailto:talk-bounces at x-query.com] Namens
Peng Yu
Verzonden: donderdag 3 november 2011 6:00
Aan: Joe Wicentowski; talk at x-query.com
Onderwerp: Re: [xquery-talk] How to invert the hierarchy of an xml?

On Wed, Nov 2, 2011 at 10:38 PM, Joe Wicentowski <joewiz at gmail.com> wrote:
> Hi Peng,
>
> Welcome to the XQuery talk mailing list.
>
>> Suppose that I have an xml where each Article has it is own Journals.
>> But since the Journals may be the same. I'd like to group the articles
>> by Journals. I'm still learning XQuery. Could anybody show me how to
>> do the conversion using XQuery?
>
> I suggest making use of XQuery 3.0's "group by" clause.  A nice
> example of "group by" happens to be on the eXist-db blog, describing
> exist-db's support for this clause
> (http://atomic.exist-db.org/HowTo/XQuery3/GroupByClause) and providing
> an example that is quite similar to yours, sans the need to filter out
> the Journal child of the Article element in the results.  Chances are
> folks will suggest more elegant approaches to that portion of the
> code, but this query does the trick.  Below is the code for your case.
>
> Cheers,
> Joe
>
>
> xquery version "3.0";

Is the above line necessary? I use the following command, where
main.xq include all the XQuery code except the above line. Everything
works fine. (httpclient.sh is from eXist-db)

httpclient.pl -u admin -p FyDi3QfBON -q < main.xq

Now suppose, that I have the elements Title and TitleLong in Journal.
I want to group by both Title and TitleLong. There are a number of
things that are different from the simpler case. I'm not familiar with
the syntax enough to know what I should use. Would you please let me
know what XQuery I should use to do the transformation? Thanks!


<Library>
    <Article>
      <ArticleTitle>title1</ArticleTitle>
      <Author>author1</Author>
      <Journal>
        <Title>journal1</Title>
        <TitleLong>journal1long</TitleLong>
        <Issue>i1</Issue>
      </Journal>
    </Article>
    <Article>
      <ArticleTitle>title2</ArticleTitle>
      <Author>author2</Author>
      <Journal>
        <Title>journal1</Title>
        <TitleLong>journal1long</TitleLong>
        <Issue>i2</Issue>
      </Journal>
    </Article>
    <Article>
      <ArticleTitle>title3</ArticleTitle>
      <Author>author3</Author>
      <Journal>
        <Title>journal2</Title>
        <TitleLong>journal2long</TitleLong>
        <Issue>i3</Issue>
      </Journal>
    </Article>
    <Article>
      <ArticleTitle>title4</ArticleTitle>
      <Author>author4</Author>
      <Journal>
        <Title>journal2</Title>
        <TitleLong>journal2long</TitleLong>
        <Issue>i4</Issue>
      </Journal>
    </Article>
</Library>


=========I want it to be converted to this
<Library>
  <Journal title="journal1" title-long="journal1long">
    <Article>
      <ArticleTitle>title1</ArticleTitle>
      <Author>author1</Author>
      <Issue>i1</Issue>
    </Article>
    <Article>
      <ArticleTitle>title2</ArticleTitle>
      <Author>author2</Author>
      <Issue>i2</Issue>
    </Article>
  </Journal>
  <Journal title="journal2" title-long="journal2long">
    <Article>
      <ArticleTitle>title3</ArticleTitle>
      <Author>author3</Author>
      <Issue>i3</Issue>
    </Article>
    <Article>
      <ArticleTitle>title4</ArticleTitle>
      <Author>author4</Author>
      <Issue>i4</Issue>
    </Article>
  </Journal>
</Library>




--
Regards,
Peng

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