Changes

This [[Module Library|XQuery Module]] contains functions for parsing and evaluating XQuery strings and modules at runtime, and to run code in parallel.

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/>All errors are assigned to the <code><nowiki>http://basex.org/errors</nowiki></code> namespace, which is statically bound to the {{Code|bxerr}} prefix.

=FunctionsEvaluation=

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|{{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(xs:string, xs:string*)?|item()*}}<br />|-valign="top"

|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:

* {{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}}.|-valign="top"

|{{Error|BXXQ0001update|#Errors}} the query contains [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|BXXQ0003permission|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|BXXQ0004timeout|#Errors}} query execution exceeded timeout or .<br/>{{Error|limit|#Errors}} query execution exceeded memory limit.<br/>{{Error|BXXQ0005nested|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.|-valign="top"

<pre classsyntaxhighlight lang='brush:"xquery'">xquery:eval("//country", map { '': db:openget('factbook') })</presyntaxhighlight>

<pre classsyntaxhighlight lang='brush:"xquery'">

</presyntaxhighlight>

<pre classsyntaxhighlight lang='brush:"xquery'">

</presyntaxhighlight>

==xquery:eval-update==

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|{{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(xs:string, xs:string*)?|item()*}}<br />|-valign="top"

|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{{Function||xquery:eval]]}}.|-valign="top"

|{{Error|BXXQ0002update|#Errors}} the query contains no [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|BXXQ0003permission|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|BXXQ0004timeout|#Errors}} query execution exceeded timeout or .<br/>{{Error|limit|#Errors}} query execution exceeded memory limit.<br/>{{Error|BXXQ0005nested|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.|- valign="top"| '''Examples'''|* Removes entries from a temporary databases and returns an info string:<syntaxhighlight lang="xquery">xquery:eval-update(" delete node db:get('tmp')/*, update:output('TEMPORARY DATABASE WAS CLEANED UP')")</syntaxhighlight>

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|{{Func|xquery:parse|$query as xs:stringanyAtomicType|item()*?}}<br />{{Func|xquery:parse|$query as xs:stringanyAtomicType, $options as map(*)?|item()?}}<br />|-valign="top"

|Parses the specified {{Code|$query}} string as XQuery module and returns the resulting query plan. If the query is of type {{Code|xs:anyURI}}, the module located at this URI will be retrieved (a relative URI will be resolved against the static base URI). Otherwise, the input is expected to be of type {{Code|xs:string}}. The {{Code|$options}} parameter influences the output:

* {{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 enabled, the line/column and file uri will be adopted from the raised error.* {{Code|falsebase-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}}.|-valign="top"

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<pre classsyntaxhighlight lang='brush:"xml'">

</presyntaxhighlight>|} ==xquery:parse-uri== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|xquery:parse-uri|$uri as xs:string|item()*}}<br />{{Func|xquery:parse-uri|$uri as xs:string, $options as map(*)|item()*}}<br />|-| '''Summary'''|Parses the XQuery module located at {{Code|$uri}} and returns the resulting query plan. A relative URI will be resolved against the static base URI of the query. The rules for the {{Code|$options}} parameter are the same as for [[#xquery:parse|xquery:parse]].|-| '''Errors'''|Any error that may occur while parsing the query.|} ==xquery:invoke== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|xquery:invoke|$uri as xs:string|item()*}}<br />{{Func|xquery:invoke|$uri as xs:string, $bindings as map(*)?|item()*}}<br />{{Func|xquery:invoke|$uri as xs:string, $bindings as map(*)?, $options as map(*)|item()*}}<br />|-| '''Summary'''|Evaluates the XQuery module located at {{Code|$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|BXXQ0001|#Errors}} the expression contains [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|BXXQ0003|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|BXXQ0004|#Errors}} query execution exceeded timeout.<br/>{{Error|BXXQ0005|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.

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.

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<pre classsyntaxhighlight lang='brush:"xquery'">

</presyntaxhighlight>

<pre classsyntaxhighlight lang='brush:"xquery'">let $funcs xquery:=fork-join(

let $url := 'http://url.com/path/' || $segment

return xquery:fork-join($funcs)</presyntaxhighlight>|-valign="top"

|{{Error|BXXQ0006error|#Errors}} an unexpected error occurred.

|-valign="top"|{{Code|BXXQ0001}}|The specified query contains [[XQuery Update#Updating Expressions|updating expressions]].|-|{{Code|BXXQ0002}}|The specified query contains no [[XQuery Update#Updating Expressions|updating expressions]].|-|{{Code|BXXQ0003permission}}

|-valign="top"|{{Code|BXXQ0004update}}|[[XQuery Update#Updating Expressions|updating expression]] found or expected.|- valign="top"|{{Code|timeout}}|Query execution exceeded timeout or .|- valign="top"|{{Code|memory}}|Query execution exceeded memory limit.|-valign="top"|{{Code|BXXQ0005nested}}

|-valign="top"|{{Code|BXXQ0006error}}

 * Added: [[#xquery:fork-join{{Function||xquery:fork-join]]}}* Updated: [[#xquery:eval{{Function||xquery:eval]]}}: {{Code|base-uri}} option added

* Deleted: xquery:type (moved to [[Profiling Module]])

 * Added: [[#xquery:parse-uri{{Function||xquery:parse-uri]]}}* Updated: [[#xquery:parse{{Function||xquery:parse]]}}: {{Code|pass}} option added

 * Added: [[#xquery:update, {{Function|xquery:update]], [[#xquery:parse|xquery:parse]]}}* Deleted: [[#xquery:evaluate|xquery:evaluate]] (opened databases will now be closed by main query)

 * Added: [[#xquery:evaluate{{Function||xquery:evaluate]]}}