MarkLogic - How to insert element into XML - xquery

How to insert the node in XML.
let $a := <a><b>bbb</b></a>)
return
xdmp:node-insert-after(doc("/example.xml")/a/b, <c>ccc</c>);
Expected Output:
<a><c>ccc</c><b>bbb</b></a>
Please help to get the output.

You should be using xdmp:node-insert-before I believe in the following way:
xdmp:document-insert('/example.xml', <a><b>bbb</b></a>);
xdmp:node-insert-before(fn:doc('/example.xml')/a/b, <c>ccc</c>);
fn:doc('/example.xml');
(: returns <a><c>ccc</c><b>bbb</b></a> :)

Nodes are immutable, so in-memory mutation can only be done by creating a new copy.
The copy can use the unmodified contained nodes from the original:
declare function local:insert-after(
$prior as node(),
$inserted as node()+
) as element()
{
let $container := $prior/parent::element()
return element {fn:node-name($container)} {
$container/namespace::*,
$container/attribute(),
$prior/preceding-sibling::node(),
$prior,
$inserted,
$prior/following-sibling::node()
}
};
let $a := <a><b>bbb</b></a>
return local:insert-after($a//b, <c>ccc</c>)
Creating a copy in memory and then inserting the copy is faster than inserting and modifying a document in the database.
Depending on how many documents are inserted, the difference could be significant.
There are community libraries for copying with changes, but sometimes it's as easy to write a quick function (recursive where necessary).

You can use below code to insert the element into the XML:
xdmp:node-insert-child(fn:doc('directory URI'),element {fn:QName('http://yournamesapce','elementName') }{$elementValue})
Here we use fn:QName to remove addition of xmlns="" in added node.

Related

eXist-db serialize is expand-xincludes=no ignored?

In eXist-db 4.4, Xquery 3.1, I am compressing a number of XML files to a .zip in a directory. The compression process uses serialize().
The XML files have some large xincludes which according to the documentation are automatically processed in serializing. I have attempted to 'turn off' the xinclude serialization in two places in the code (prologue declare and map), but the serializer is still outputting all xincludes:
declare option exist:serialize "expand-xincludes=no";
declare function zip:get-entries-for-zip()
{
(: get documents prefixed by 'MS609' :)
let $pref := "MS609"
(: get list of document names :)
let $doclist := xmldb:get-child-resources($globalvar:URIdata)[starts-with(., $pref)]
(: output serialized entries :)
let $entries :=
for $n in $doclist
return
<entry name="{$n}" type='text' method='store'>
{serialize(doc(concat($globalvar:URIdata, "/", $n)), map { "method": "xml", "expand-xincludes": "no"})}
</entry>
return $entries
};
The XML data with xincludes to reproduce this problem can be found here http://medieval-inquisition.huma-num.fr/downloads under the description "BM MS609 Edition (tei-xml)".
Many thanks in advance.
The expand-xincludes serialization parameter is specific to eXist and, as such (or at least at present), cannot be set using the fn:serialize() function. Instead, use the util:serialize() function:
util:serialize($document, "expand-xincludes=no")
Alternatively, since you're ultimately interested in zipping the contents of a collection, you can skip the explicit serialization step, declare your serialization options in the query's prolog (or set it inline using util:declare-option()), and simply provide the compression:zip() function the URI path(s) to the collections/documents you want to zip. For example:
xquery version "3.1";
declare option exist:serialize "expand-xincludes=no";
let $sources := "/db/apps/my-app/my-data" (: or a sequence of paths to individual docs:) ! xs:anyURI(.)
let $preserve-collection-structure := false()
let $zip := compression:zip($sources, $preserve-collection-structure),
return
xmldb:store("/db", "my-data.zip", $zip)
For more on serialization options in eXist, see my earlier answer to a similar question: https://stackoverflow.com/a/49290616/659732.

Recursive copy of a folder with XQuery

I have to copy an entire project folder inside the MarkLogic server and instead of doing it manually I decided to do it with a recursive function, but is becoming the worst idea I have ever had. I'm having problems with the transactions and with the syntax but being new I don't find a true way to solve it. Here's my code, thank you for the help!
import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";
declare option xdmp:set-transaction-mode "update";
declare function local:recursive-copy($filesystem as xs:string, $uri as xs:string)
{
for $e in xdmp:filesystem-directory($filesystem)/dir:entry
return
if($e/dir:type/text() = "file")
then dls:document-insert-and-manage($e/dir:filename, fn:false(), $e/dir:pathname)
else
(
xdmp:directory-create(concat(concat($uri, data($e/dir:filename)), "/")),
local:recursive-copy($e/dir:pathname, $uri)
)
};
let $filesystemfolder := 'C:\Users\WB523152\Downloads\expath-ml-console-0.4.0\src'
let $uri := "/expath_console/"
return local:recursive-copy($filesystemfolder, $uri)
MLCP would have been nice to use. However, here is my version:
declare option xdmp:set-transaction-mode "update";
declare variable $prefix-replace := ('C:/', '/expath_console/');
declare function local:recursive-copy($filesystem as xs:string){
for $e in xdmp:filesystem-directory($filesystem)/dir:entry
return
if($e/dir:type/text() = "file")
then
let $source := $e/dir:pathname/text()
let $dest := fn:replace($source, $prefix-replace[1], $prefix-replace[2])
let $_ := xdmp:document-insert($source,
<options xmlns="xdmp:document-load">
<uri>{$dest}</uri>
</options>)
return <record>
<from>{$source}</from>
<to>{$dest}</to>
</record>
else
local:recursive-copy($e/dir:pathname)
};
let $filesystemfolder := 'C:\Temp'
return <results>{local:recursive-copy($filesystemfolder)}</results>
Please note the following:
I changed my sample to the C:\Temp dir
The output is XML only because by convention I try to do this in case I want to analyze results. It is actually how I found the error related to conflicting updates.
I chose to define a simple prefix replace on the URIs
I saw no need for DLS in your description
I saw no need for the explicit creation of directories in your use case
The reason you were getting conflicting updates because you were using just the filename as the URI. Across the whole directory structure, these names were not unique - hence the conflicting update on double inserts of same URI.
This is not solid code:
You would have to ensure that a URI is valid. Not all filesystem paths/names are OK for a URI, so you would want to test for this and escape chars if needed.
Large filesystems would time-out, so spawning in batches may be useful.
A an example, I might gather the list of docs as in my XML and then process that list by spawning a new task for every 100 documents. This could be accomplished by a simple loop over xdmp:spawn-function or using a library such as taskbot by #mblakele

How to set the value of one field to another filed in using XQuery

Very new to XQuery and MarkLogic, what is the XQuery version of the following statement?
update all_the_records
set B_field = A_field
where B_field is null and A_field is not null
Something like this might get you started. But remember that you're working with trees, not tables. Things are generally more complicated because of that extra dimension.
for $doc in collection()/doc[not(b)][a]
let $a as element() := $doc/a
return xdmp:node-insert-child($doc, element b { $a/#*, $a/node() })

Xquery - what is wrong here

I would like the node replace to act on the $person variable. What do I need to change?
The following code should change the name of the people in the sequence to X.
declare function local:ChangeName($person)
{
xdmp:node-replace($person//Name/text, text { "X" } )
<p>{$person}</p>
};
let $b := <Person>
<Name>B</Name>
<IsAnnoying>No</IsAnnoying>
</Person>
let $j := <Person>
<Name>J</Name>
<IsAnnoying>No</IsAnnoying>
</Person>
let $people := ($b, $j)
return $people ! local:ChangeName(.)
xdmp:node-replace() only operates on persisted documents, not on in-memory documents.
Your local:ChangeName() function could construct the Person and Name elements but copying the IsAnnoying element, as in:
declare function local:ChangeName($person)
{
<p>
<Person>
<Name>X</Name>
{$person//IsAnnoying}
</Person>
</p>
};
For more complex transformations, consider a recursive typeswitch or XSLT transform.
As Erik noted above, you can't apply the xdmp update functions to in-memory nodes. If you have a strong need to to do in-memory node updates, Ryan Grimm's memupdate library can come in handy. It basically does the grunt work of the recursive traversal for you. But beware, in-memory updates do not scale to large documents because it requires making a copy to do an update.
https://github.com/marklogic/commons/tree/master/memupdate
I don't have a ML instance running, so I couldn't test it (maybe there are more issues), but it has to be
$person//Name/text()
instead of
$person//Name/text
The Xpath:
$person//Name/text
should be:
$person//Name/text()
The XPath is looking to replace the text node, which doesn't exist.
Also note that the results of xdmp:node-replace will not be visible in the same transaction. To see the results you need to start a new transaction.

To remove the node but keep the value inside intact through XQuery

I have a content.xml modelled as below
<root>
<childnode>
Some text here
</childnode>
</root>
I am trying to remove the <childnode> and update the content.xml with only the value of it
so the output looks like
<root>
Some Text here
</root>
I wrote a function to perform this but anytime I run it it gives me error as "unexpected token: modify". I was thinking of a way to accomplish this without using functx functions.
xquery version "1.0";
declare namespace request="http://exist-db.org/xquery/request";
declare namespace file="http://exist-db.org/xquery/file";
declare namespace system="http://exist-db.org/xquery/system";
declare namespace util="http://exist-db.org/xquery/util";
declare namespace response="http://exist-db.org/xquery/response";
declare function local:contentUpdate() {
let $root := collection('/lib/repository/content')//root/childNode
let $rmChild := for $child in $root
modify
(
return rename node $child as ''
)
};
local:updateTitle()
Thanks in advance
There are multiple problems with your query:
Updating functions must be declared as updating.
You're calling another function than you defined (probably you didn't notice as there still have been syntax errors).
Rename node expects some element (or processing instruction, attribute) as target, the empty string is not allowed.
At least BaseX doesn't allow updating statements when defining code as XQuery 1.0. Maybe exist doesn't care about this, try adding it if you need to know.
You do not want to rename, but replace all <childnode />s with its contents, use replace node.
This code fixes all these problems:
declare updating function local:contentUpdate() {
let $root := collection('/lib/repository/content')
return
for $i in $root//childnode
return
replace node $i with $i/data()
};
local:contentUpdate()
eXist-db's XQuery Update syntax is documented at http://exist-db.org/exist/update_ext.xml. Note that this syntax predates the release of the XQuery Update Facility 1.0, so the syntax is different and remains unique to eXist-db.
The way to do what you want in eXist-db is as follows:
xquery version "1.0";
declare function local:contentUpdate() {
let $root := doc('/db/lib/repository/content/content.xml')/root
return
update value $root with $root/string()
};
local:contentUpdate()
The primary changes, compared to your original code, are:
Inserted the eXist-db syntax for your update
Prepended '/db' to your collection name, as /db is the root of the database in eXist-db; replaced the collection() call with a doc() call, since you stated you were operating on a single file, content.xml
Changed //root to /root, since "root" is the root element, so the // (descendant-or-self) axis is extraneous
Replaced updateTitle() with the actual name of the function, contentUpdate
Removed the extraneous namespace declarations
For more on why I used $root/string(), see http://community.marklogic.com/blog/text-is-a-code-smell.

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