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.

=FunctionsDynamic Evaluation=

|{{Func|xquery:eval|$query as xs:string|item()*}}<br />{{Func|xquery:eval|$query as xs:string, $bindings as map(*)?|item()*}}<br />{{Func|xquery:eval|$query as xs:string, $bindings as map(*)?, $options as map(xs:string, xs:string*)?|item()*}}<br />

* {{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 URI will be used when resolving relative URIs by functions such as {{Code|fn:doc}}. Added with * {{VersionCode|8pass}}: passes on the original error info (line and column number, optional file uri).5By default, this option is {{Code|false}}.

|{{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.

==xquery:eval-update==

|{{Func|xquery:eval-update|$query as xs:string|item()*}}<br />{{Func|xquery:eval-update|$query as xs:string, $bindings as map(*)?|item()*}}<br />{{Func|xquery:eval-update|$query as xs:string, $bindings as map(*)?, $options as map(xs:string, xs:string*)?|item()}}<br />

|{{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.

|{{Func|xquery:parse|$query as xs:string|item()*?}}<br />{{Func|xquery:parse|$query as xs:string, $options as map(*)?|item()?}}<br />

|{{Func|xquery:parse-uri|$uri as xs:string|item()*?}}<br />{{Func|xquery:parse-uri|$uri as xs:string, $options as map(*)?|item()*?}}<br />

=Parallelized Execution=xquery:invoke== {{Mark|Updated with Version 8.5}}: Relative URIs will always be resolved against the static base URI of the query.

{| width='100%'|-| width='120' | '''Signatures'''|{{Func|xquery:invoke|$uri as xs:string|item()*}}<br />{{Func|xquery:invoke|$uri as xs:stringParallel query execution is recommendable if you have various calls that require a lot of time, $bindings as map(*)|itembut that cannot be sped up by rewriting the code. This is e. g. the case if external URLs are called. If you are parallelizing local data reads ()*}}<br />{{Func|xquery:invoke|$uri such as xs:string, $bindings as map(*the access to a database), $options as map(*)|item()*}}<br />|single-| '''Summary'''|Evaluates the XQuery module located at {{Code|$uri}} at runtime and returns the resulting items. A relative URI threaded queries will usually be faster, because parallelized access to disk data often results in randomized access patterns, which will rarely be resolved against optimized by the static base URI caching strategies of HDDs, SSDs, or 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 queryoperating system.|}

|This function executes the supplied (non-updating) functions in parallel.<br/>Parallel query execution is recommendable if you have various calls that require a lot of time, but 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 accessing a database), your single-threaded query will usually be faster, because parallelized access to disk data will often lead to randomized access patterns, which can hardly be optimized by your HD or SSD.

let $funcs xquery:=fork-join(

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

return xquery:fork-join($funcs)

|{{Error|unexpectederror|#Errors}} an unexpected error occurred while running a query or function in a separate thread.

|{{Code|BXXQ0001permission}}|The specified Insufficient permissions for evaluating the query contains [[XQuery Update#Updating Expressions|updating expressions]].

|{{Code|BXXQ0002update}}|The specified query contains no [[XQuery Update#Updating Expressions|updating expressionsexpression]]found or expected.

|{{Code|BXXQ0003timeout}}|Insufficient permissions for evaluating the queryQuery execution exceeded timeout.

|{{Code|BXXQ0004memory}}|Query execution exceeded timeout or memory limit.

|{{Code|BXXQ0005nested}}

 * Added: [[#xquery:update|xquery:update]], [[#xquery:parse|xquery:parse]]