问题
Hi I am new to marklogic and in Xquery world. I am not able to think of starting point to write the following logic in Marklogic Xquery. I would be thankful if somebody can give me idea/sample so I can achieve the following:
I want to Query A.XML based on a word lookup in B.XML. Query should produce C.XML. The logic should be as follows:
A.XML
<root>
<content> The state passed its first ban on using a handheld cellphone while driving in 2004 Nokia Vodafone Nokia Growth Recession Creicket HBO</content>
</root>
B.XML
<WordLookUp>
<companies>
<company name="Vodafone">Vodafone</company>
<company name="Nokia">Nokia</company>
</companies>
<topics>
<topic group="Sports">Cricket</topic>
<topic group="Entertainment">HBO</topic>
<topic group="Finance">GDP</topic>
</topics>
<moods>
<mood number="4">Growth</mood>
<mood number="-5">Depression</mood>
<mood number="-3">Recession</mood>
</moods>
C.XML (Result XML)
<root>
<content> The state passed its first ban on using a handheld cellphone while driving in 2004 Nokia Vodafone Nokia Growth Recession Creicket HBO</content>
<updatedElement>
<companies>
<company count="1">Vodafone</company>
<company count="2">Nokia</company>
</companies>
<mood>1</mood>
<topics>
<topic count="1">Sports</topic>
<topic count="1">Entertainment</topic>
</topics>
<word-count>22</word-count>
</updatedElement>
</root>
Search each company/text() of A.xml in B.xml, if match found create tag: TAG {company count="Number of occurrence of that word"}company/@name {/company}
Search each topic/text() of A.xml in B.xml, if match found create tag TAG {topic topic="Number of occurrences of that word"}topic/@group{/topic}
Search each mood/text() of A.xml in B.xml, if match found [occurrences of first word * {/mood[first word]/@number}] + [occurrences of second word * {/mood[second word]/@number})]....
get the word count of element.
回答1:
This is simpler/shorter and fully compliant XQuery not containing any implementation extensions, which make it work with any compliant XQuery 1.0 processor:
let $content := doc('file:///c:/temp/delete/A.xml')/*/*,
$lookup := doc('file:///c:/temp/delete/B.xml')/*,
$words := tokenize($content, '\W+')[.]
return
<root>
{$content}
<updatedElement>
<companies>
{for $c in $lookup/companies/*,
$occurs in count(index-of($words, $c))
return
if($occurs)
then
<company count="{$occurs}">
{$c/text()}
</company>
else ()
}
</companies>
<mood>
{
sum($lookup/moods/*[false or index-of($words, data(.))]/@number)
}
</mood>
<topics>
{for $t in $lookup/topics/*,
$occurs in count(index-of($words, $t))
return
if($occurs)
then
<topic count="{$occurs}">
{data($t/@group)}
</topic>
else ()
}
</topics>
<word-count>{count($words)}</word-count>
</updatedElement>
</root>
When applied on the provided files A.xml and B.XML (contained in the local directory c:/temp/delete), the wanted, correct result is produced:
<root>
<content> The state passed its first ban on using a handheld cellphone while driving in 2004 Nokia Vodafone Nokia Growth Recession Cricket HBO</content>
<updatedElement>
<companies>
<company count="1">Vodafone</company>
<company count="2">Nokia</company>
</companies>
<mood>1</mood>
<topics>
<topic count="1">Sports</topic>
<topic count="1">Entertainment</topic>
</topics>
<word-count>22</word-count>
</updatedElement>
</root>
回答2:
This was a fun one, and I learned a few things in the process. Thanks!
Note: to get the results you wanted, I fixed a typo in A.xml ("Creicket" -> "Cricket").
The following solution uses two MarkLogic-specific functions:
cts:highlight(for replacing matching text with nodes which you can then count)cts:tokenize(for breaking up a given string into word, space, and punctuation parts)
It also includes some powerful magic specific to those two functions, respectively:
- the dynamic binding of the special variable
$cts:text(which isn't really necessary for this particular use case, but I digress), and - the data model extension which adds these subtypes of
xs:string:cts:word,cts:space, andcts:punctuation.
Enjoy!
xquery version "1.0-ml";
(: Generic function using MarkLogic's ability to find query matches within a single node :)
declare function local:find-matches($content, $search-text) {
cts:highlight($content, $search-text, <MATCH>{$cts:text}</MATCH>)
//MATCH
};
(: Generic function using MarkLogic's ability to tokenize text into words, punctuation, and spaces :)
declare function local:get-words($text) {
cts:tokenize($text)[. instance of cts:word]
};
(: The rest of this is pure XQuery :)
let $content := doc("A.xml")/root/content,
$lookup := doc("B.xml")/WordLookUp
return
<root>
{$content}
<updatedElement>
<companies>{
for $company in $lookup/companies/company
let $results := local:find-matches($content, string($company))
where exists($results)
return
<company count="{count($results)}">{string($company/@name)}</company>
}</companies>
<mood>{
sum(
for $mood in $lookup/moods/mood
let $results := local:find-matches($content, string($mood))
return count($results) * $mood/@number
)
}</mood>
<topics>{
for $topic in $lookup/topics/topic
let $results := local:find-matches($content, string($topic))
where exists($results)
return
<topic count="{count($results)}">{string($topic/@group)}</topic>
}</topics>
<word-count>{
count(local:get-words($content))
}</word-count>
</updatedElement>
</root>
Let me know if you have any follow-up questions about how all the above works. At first, I was inclined to use cts:search or cts:contains, which are the bread and butter for search in MarkLogic. But I realized that this example wasn't so much about search (finding documents) as it was about looking up matching text within an already-given document. If you needed to extend this somehow to aggregate across a large number of documents, then you'd want to look into the additional use of cts:search or cts:contains.
One final caveat: if you think your content might have <MATCH> elements already, you'll want to use a different element name when calling cts:highlight (a name which you can guarantee won't conflict with your content's existing element names). Otherwise, you'll potentially get the wrong number of results (higher than the accurate count).
ADDENDUM:
I was curious if this could be done without cts:highlight, given that cts:tokenize already breaks up the text into all the words for you. The same result is produced using this alternative implementation of local:find-matches (provided you swap the order of the function declarations because one depends on the other):
(: Find word matches by comparing them one-by-one :)
declare function local:find-matches($content, $search-text) {
local:get-words($content)[cts:stem(.) = cts:stem($search-text)]
};
It uses cts:stem to normalize the given word to its stem, so, for example searching for "pass" will match "passed", etc. However, this still won't work for multi-word (phrase) searches. So to be safe, I'd stick with using cts:highlight, which, like cts:search and cts:contains, can handle any cts:query you give it (including simple word/phrase searches like we do above).
回答3:
Might make sense to step back and ask if you might be better served modeling your data and or documents for use with a document oriented database instead of an rdbms
来源：https://stackoverflow.com/questions/10157616/marklogic-join-query