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{{Mark|Updated with Version 9.0:}}
{{Mark|Updated with Version 9.0:}} {{code|pass}} option added.
{{Mark|Updated with Version 9.0:}} Renamed (old name: xquery:update)
|}
==xquery:invoke==
{| width='100%'
| width='120' | '''SignaturesExamples'''|{{Func|xquery* Removes entries from a temporary databases and returns an info string:invoke|$uri as xs:string|item()*}}<br /syntaxhighlight lang="xquery">{{Func|xquery:invoke|$uri as xseval-update(" delete node db:string, $bindings as map(*)?|itemopen('tmp')*}}<br />{{Func|xquery:invoke|$uri as xs:string, $bindings as map(*)?, $options as map update:output(*)?|item()*}}<br />|-| '''Summary''TEMPORARY DATABASE WAS CLEANED UP')|Evaluates the XQuery module located at {{Code|$uri}} at runtime and returns the resulting items. A relative URI will be resolved against the static base URI of the query.<br />The rules of the {{Code|$bindings}} and {{Code|$options}} parameters are the same as for [[#xquery:eval|xquery:eval]].|-")| '''Errors'''|{{Error|update|#Errors}} the expression contains [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|permission|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|timeout|#Errors}} query execution exceeded timeout.<br/>{{Error|nested|#Errors}} nested query evaluation is not allowed.<br/syntaxhighlight>Any other error that may occur while evaluating the query.
{{Mark|Updated with Version 9.0:}} {{code|base-uri}} option added.
{{Mark|Updated with Version 9.0:}} {{code|base-uri}} option added.
return xquery:fork-join($funcs)</presyntaxhighlight>
{{Mark|Updated with Version 9.0:}}
no edit summary
This [[Module Library|XQuery Module]] contains functions for parsing and evaluating XQuery strings and modules at runtime, and to run code in parallel.
=Conventions=
All functions and errors in this module are assigned to the <code><nowiki>http://basex.org/modules/xquery</nowiki></code> namespace, which is statically bound to the {{Code|xquery}} prefix.<br/>
=FunctionsDynamic Evaluation=
==xquery:eval==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|xquery:eval|$query as xs:stringanyAtomicType|item()*}}<br />{{Func|xquery:eval|$query as xs:stringanyAtomicType, $bindings as map(*)?|item()*}}<br />{{Func|xquery:eval|$query as xs:stringanyAtomicType, $bindings as map(*)?, $options as map(*)?|item()*}}<br />
|-
| '''Summary'''
|Evaluates the supplied {{Code|$query}} string as XQuery expression and returns the resulting items.<br/>The evaluated If the query has its own query context. If a returned node is stored in a databaseof type {{Code|xs:anyURI}}, the module located at this URI will be retrieved (a main-memory copy relative URI will be returned as resultresolved against the static base URI). Otherwise, because the referenced database input is closed after query execution and will not expected to be accessible anymoreof type {{Code|xs:string}}.<br />Variables and context items can be declared via {{Code|$bindings}}. The specified keys must be QNames or strings:
* If a key is a QName, it will be directly adopted as variable name.
* It a key is a string, it may be prefixed with a dollar sign. Namespace can be specified using the [http://www.jclark.com/xml/xmlns.htm Clark Notation].
* {{Code|timeout}}: query execution will be interrupted after the specified number of seconds.
* {{Code|memory}}: query execution will be interrupted if the specified number of megabytes will be exceeded. This check works best if only one process is running at the same time. Moreover, please note that this option enforces garbage collection, so it will take some additional time, and it requires GC to be enabled in your JVM.
* {{Code|base-uri}}: set [https://www.w3.org/TR/xquery-31/#dt-static-base-uri base-uri property] for the query. This Overwrites the base URI of the query; will be used when resolving relative URIs by functions such as {{Code|fn:doc}}.
* {{Code|pass}}: passes on the original error info (line and column number, optional file uri). By default, this option is {{Code|false}}.
|-
|
* {{Code|xquery:eval("1+3")}} returns {{Code|4}}.<br />
* If a URI is supplied, the query in the specified file will be evaluated:
<syntaxhighlight lang="xquery">
xquery:eval(xs:anyURI('cleanup.xq'))
</syntaxhighlight>
* You can bind the context and e.g. operate on a certain database only:<br />
<pre classsyntaxhighlight lang='brush:"xquery'">
xquery:eval("//country", map { '': db:open('factbook') })
</presyntaxhighlight>
* The following expressions use strings as keys. All of them return 'XML':<br/>
<pre classsyntaxhighlight lang='brush:"xquery'">
xquery:eval(".", map { '': 'XML' }),
map { '{URI}xml': 'XML' }
)
</presyntaxhighlight>
* The following expressions use QNames as keys. All of them return 'XML':<br/>
<pre classsyntaxhighlight lang='brush:"xquery'">
declare namespace pref = 'URI';
let $vars := map { xs:QName('pref:xml'): 'XML' }
return xquery:eval($query, $vars)
</presyntaxhighlight>
|}
==xquery:eval-update==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|xquery:eval-update|$query as xs:stringanyAtomicType|item()*}}<br />{{Func|xquery:eval-update|$query as xs:stringanyAtomicType, $bindings as map(*)?|item()*}}<br />{{Func|xquery:eval-update|$query as xs:stringanyAtomicType, $bindings as map(*)?, $options as map(*)?|item()*}}<br />
|-
| '''Summary'''
|Evaluates {{Code|$a query}} as updating XQuery expression at runtime.<br/>All updates will be added to the [[XQuery Update#Pending Update List|Pending Update List]] of the main query and performed after the evaluation of the main query.<br />The rules of the {{Code|$bindings}} and {{Code|$options}} parameters for all arguments are the same as for [[#xquery:eval|xquery:eval]].
|-
| '''Errors'''
|{{Error|update|#Errors}} the query contains no [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|permission|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|timeout|#Errors}} query execution exceeded timeout.<br/>{{Error|limit|#Errors}} query execution exceeded memory limit.<br/>{{Error|nested|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.
|-
|}
=XQuery Parsing=xquery:invoke-update== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|xquery:invoke-update|$uri as xs:string|item()*}}<br />{{Func|xquery:invoke-update|$uri as xs:string, $bindings as map(*)?|item()*}}<br />{{Func|xquery:invoke-update|$uri as xs:string, $bindings as map(*)?, $options as map(*)?|item()*}}<br />|-| '''Summary'''|Evaluates the updating XQuery module located at {{Code|$uri}} at runtime. A relative URI will be resolved against the static base URI of the query.<br />The rules of the {{Code|$bindings}} and {{Code|$options}} parameters are the same as for [[#xquery:eval|xquery:eval]].|-| '''Errors'''|{{Error|update|#Errors}} the expression contains no [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|permission|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|timeout|#Errors}} query execution exceeded timeout.<br/>{{Error|nested|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.|}
==xquery:parse==
{| width='100%'
* {{Code|compile}}: additionally compiles the query after parsing it. By default, this option is {{Code|false}}.
* {{Code|plan}}: returns an XML representation of the internal query plan. By default, this option is {{Code|true}}. The naming of the expressions in the query plan may change over time
* {{Code|pass}}: passes on by default, the original option is {{Code|false}}. If an error info (is raised, the line and /column number, and the optional file uri)will refer to the location of the function call. By default, this If the option is {{Code|false}}enabled, the line/column and file uri will be adopted from the raised error.
* {{Code|base-uri}}: set [https://www.w3.org/TR/xquery-31/#dt-static-base-uri base-uri property] for the query. This URI will be used when resolving relative URIs by functions such as {{Code|fn:doc}}.
|-
|
* {{Code|xquery:parse("1 + 3")}} returns:
<pre classsyntaxhighlight lang='brush:"xml'">
<MainModule updating="false">
<QueryPlan compiled="false">
</QueryPlan>
</MainModule>
</presyntaxhighlight>
|}
==xquery:parse-uri==
{| width='100%'
=Parallelized Execution=
Parallel query execution is recommendable if you have various calls that require a lot of time, but that cannot be sped up by rewriting the code. This is e. g. the case if external URLs are called. If you are parallelizing local data reads (such as the access to a database), single-threaded queries will usually be faster, because parallelized access to disk data often results in randomized access patterns, which can hardly will rarely be optimized by the caching strategies of HDHDDs, SSDs, SSD or the operating system.
==xquery:fork-join==
|
* The following function sleeps in parallel; it will be finished in 1 second if your system has at least 2 cores:
<pre classsyntaxhighlight lang='brush:"xquery'">
let $f := function() { prof:sleep(1000) }
return xquery:fork-join(($f, $f))
</presyntaxhighlight>
* In the following query, up to four URLs will be requested in parallel:
<pre classsyntaxhighlight lang='brush:"xquery'">let $funcs xquery:=fork-join(
for $segment in 1 to 4
let $url := 'http://url.com/path/' || $segment
return function() { http:send-request((), $url) }
|-
|'''Errors'''
=Errors=
{| class="wikitable" width="100%"
=Changelog=
;Version 9.2
* Deleted: xquery:invoke, xquery:invoke-update (merged with [[#xquery:eval|xquery:eval]] and [[#xquery:eval-update|xquery:eval-update]])
;Version 9.0
* Updated: [[#xquery:eval|xquery:eval]]: {{Code|base-uri}} option added
* Updated: Relative URIs will always be resolved against the static base URI of the query
* Deleted: xquery:type (moved to [[Profiling Module]])
;Version 8.4
* Added: xquery:update, [[#xquery:parse|xquery:parse]]
* Deleted: [[#xquery:evaluate|xquery:evaluate]] (opened databases will now be closed by main query)
;Version 7.8.2
