Hello Mike,
Thanks a lot for your reply.
I am storing data in Marklogic using the xml I mentioned before. Here is an
simplified version of xml that I am storing in ML:
<language>
<value xml:lang="en">English value-1</value>
<value xml:lang="zh">chines word-1</value>
</language>
I want to sort in either "en" or "zh" language. I think the below statement
would work for me:
let $lang := (: language to be used in sorting :)
for $i in (: some cts to get data from ML :)
order by $i/value[@xml:lang eq $lang]
Please suggest how to go with its indexing. Which index is most prominent
in order to sort in both language.
Sorry for my ignorance if I am lacking in some most basic information.
Regards,
Ashish
On Wed, Jun 11, 2014 at 10:04 PM, Michael Blakeley <[email protected]>
wrote:
> It's not clear what it means to "sort the above xml based on the value
> element for xml:lang="zh" or xml:lang="en" depending on some inputs". The
> structure includes multiple 'language' element, each with multiple
> language-annotated 'value' elements. Do you want to sort the 'language'
> elements by 'value' and language?
>
> If so, range indexes won't help because this will be an in-memory sort
> anyway. Range indexes are only used for very specific sorts, when the
> results are coming from the database and are aligned with the range index.
> See https://docs.marklogic.com/guide/performance/order_by for details.
>
> If we're sorting in memory anyway there's no reason to set up a range
> index. The next hurdle is discussed in
> http://stackoverflow.com/questions/23769228/dynamic-sort-order-by-based-on-variable-in-xquery
> - the dynamic sort problem. Basically XQuery doesn't have a nice idiom for
> specifying dynamic sort keys. So you'll end up either building a string and
> calling xdmp:value, or enumerating every possible sort key. Neither option
> is ideal, but they both work.
>
> Here's an example of how enumeration might work. First define the language
> elements as $list and set the value of $lang that you want to test:
>
> let $list as element(language)+ := ...
> let $lang as xs:string := 'en'
>
> Then sort:
>
> for $i in $list
> order by
> if ($lang eq 'en') then $i/value[@xml:lang eq $lang] else ()
> empty least
> collation "http://marklogic.com/collation/en";,
> if ($lang eq 'zh') then $i/value[@xml:lang eq $lang] else ()
> empty least
> collation "http://marklogic.com/collation/zh";
> return $i
>
> You can change the behavior around empty values and tweak the collations.
> You *can't* use a variable as a collation string: for no good reason that I
> know of, collations in an order-by clause have to be string literals. So
> there has to be a separate sort key with its own if-then-else and collation
> for every distinct collation that you want to support. This gets tedious.
>
> Or you could build a FLWOR as a string and call xdmp:value on it. This way
> we *can* use a variable for the collation string, but there'll be some
> overhead from calling xdmp:value and some risk of building an invalid FLWOR
> expression.
>
> let $collation :=
> switch($lang)
> case 'en' return "http://marklogic.com/collation/en";
> case 'zh' return "http://marklogic.com/collation/zh";
> (: Add more cases as needed. :)
> default return error((), 'UNEXPECTED', $lang)
> let $xqy := 'for $i in $list order by $i/value[@xml:lang eq $lang]'
> ||' collation "'||$collation||'"'
> ||' return $i'
> return xdmp:value($xqy)
>
> -- Mike
>
> On 10 Jun 2014, at 23:56 , Ashish Bhardwaj <[email protected]>
> wrote:
>
> > Hi David,
> >
> > Thanks for your response. Here is the xml:
> > <multilanguage>
> > <language><value xml:lang="zh">丁2橡胶</value> <value
> xml:lang="en">third</value></language>
> > <language><value xml:lang="zh">丙酸异辛酯</value> <value
> xml:lang="en">tenth</value></language>
> > <language><value xml:lang="zh">丁烯</value> <value
> xml:lang="en">first</value></language>
> > <language> <value xml:lang="en">sixth</value></language>
> > <language><value xml:lang="zh">丙酸 丁酯</value> <value
> xml:lang="en">seventh</value></language>
> > <language><value xml:lang="zh">丁苯胶</value> <value
> xml:lang="en">fourth</value></language>
> > <language><value xml:lang="en">eleventh</value></language>
> > <language><value xml:lang="zh">丁1橡胶</value><value
> xml:lang="en">second</value></language>
> > <language><value xml:lang="zh">丙</value> <value
> xml:lang="en">1</value></language>
> > <language><value xml:lang="zh">丙~</value> <value
> xml:lang="en">fifth</value></language>
> > <language><value xml:lang="zh">丙 乙酯</value> <value
> xml:lang="en">eighth</value></language>
> > </multilanguage>
> >
> > I need to sort the above xml based on the value element for
> xml:lang="zh" or xml:lang="en" depending on some inputs.
> >
> > How can I do this in MarkLogic.
> > What FLWOR will be needed for both language sorting.
> >
> > Also I am thinking to have to range indexes with different collations(1
> for zh and other for en) is this the right way to solve this.
> >
> > Regards,
> > Ashish
> >
> >
> > On Tue, Jun 10, 2014 at 4:14 PM, David Ennis <[email protected]>
> wrote:
> > HI.
> >
> > Separate from language support, you can specify the collation to use on
> specific string indexes.
> >
> > https://docs.marklogic.com/guide/search-dev/encodings_collations
> >
> > In my opinion, This is really the magic needed for granular control
> sorting.
> >
> > As well as defaults, you can define the collation on the index and then
> refer to a specific collation in your search.
> >
> > Let me know if this helps. Otherwise, provide an XML sample and how you
> want it sorted. Then there will be enough information for someone to
> provide a proper sample.
> >
> > Kind Regards,
> > David Ennis
> >
> >
> > On 10 June 2014 12:16, Ashish Bhardwaj <[email protected]> wrote:
> > Hi,
> >
> > Can anyone tell me what are the ways of doing a language specific
> sorting on a particular data using Marklogic XQuery?
> >
> > I am new to MarkLogic and have gone through a lot of documentation
> around collations in Marklogic but how to run a query which can do language
> specific sorting is something which is nowhere mentioned in documentation.
> I would appreciate if someone can give me a few examples.
> >
> > Thanks,
> > Ashish
> >
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