Changes

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

|{{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 itemmap(xs:string, xs:string)|item()*}}<br />

|Evaluates the supplied {{Code|$query}} string as XQuery expression at runtime and returns the resulting items.<br/>The evaluated query has its own query context. If a returned node is stored in a database, a main-memory copy will be returned as result, because the referenced database is closed after query execution and will not be accessible anymore.<br />Variables and context items can be declared via {{Code|$bindings}}. The specified keys must be QNames or strings, the values can be arbitrary item sequences:* variables specified as QNames If a key is a QName, it will be directly interpreted adopted as variable name.* variables specified as xs: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].

The {{Code|$options}} parameter contains evaluation options, which can either be specified* as children of an {{Code|<xquery:options/>}} element:<pre class="brush:xml"><xquery:options> <xquery:permission value="none"/></xquery:options></pre>* as map, which contains all key/value pairs:<pre class="brush:xml">map { "permission" := "none" }</pre>The following options are available:* {{Code|permission}}: the query will be evaluated with the specified permissions (see [[User Management]]).

|{{Error|BXXQ0001|#Errors}} the query contains [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|FOTY0013BXXQ0003|#Errors}} insufficient permissions for evaluating the expression yields function itemsquery.<br/>{{Error|BXXQ0004|#Errors}} query execution exceeded timeout or memory limit.<br/>{{Error|BXXQ0005|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.

xquery:eval("//country", map { '' := db:open('factbook') })

xquery:eval("declare variable $xml external; $xml", map { 'xml' := 'XML' }),

==xquery:evaluateupdate== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|xquery:update|$query as xs:string|item()*}}<br />{{Func|xquery:update|$query as xs:string, $bindings as map(*)?|item()*}}<br />{{Func|xquery:update|$query as xs:string, $bindings as map(*)?, $options as map(xs:string, xs:string)|item()}}<br />|-| '''Summary'''|Evaluates {{Code|$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 are the same as for [[#xquery:eval|xquery:eval]].|-| '''Errors'''|{{Error|BXXQ0002|#Errors}} the query contains no [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|BXXQ0003|#Errors}} insufficient permissions for evaluating the query.<br/>{{Error|BXXQ0004|#Errors}} query execution exceeded timeout or memory limit.<br/>{{Error|BXXQ0005|#Errors}} nested query evaluation is not allowed.<br/>Any other error that may occur while evaluating the query.|} ==xquery:parse== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|xquery:parse|$query as xs:string|item()*}}<br />{{Func|xquery:parse|$query as xs:string, $options as map(*)|item()}}<br />|-| '''Summary'''|Parses the specified {{Code|$query}} string as XQuery module and returns the resulting query plan. The {{Code|$options}} parameter influences the output:* {{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 the original error info (line and column number, optional file uri). By default, this option is {{Code|false}}.|-| '''Errors'''|Any error that may occur while parsing the query.|-| '''Examples'''|* {{Code|xquery:parse("1 + 3")}} returns:<pre class='brush:xml'><MainModule updating="false"> <QueryPlan compiled="false"> <Arith op="+"> <Int value="1" type="xs:integer"/> <Int value="3" type="xs:integer"/> </Arith> </QueryPlan></MainModule></pre>|}

{{Mark|Updated with Version 7.8.2==xquery:}} {{Code|$options}} argument added.parse-uri==

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

|Evaluates Parses the XQuery module located at {{Code|$queryuri}} as XQuery expression at runtime and returns the resulting itemsquery plan. A relative URI will be resolved against the static base URI of the query.<br/>The function differs from rules for the {{Code|$options}} parameter are the same as for [[#xquery:evalparse|xquery:evalparse]] in two ways:* All items will be directly returned and not duplicated. This way, queries will be evaluated faster, and database nodes will retain their node identity.* In exchange, it is not possible to open new databases.

|{{Error|BXXQ0001|#Errors}} Any error that may occur while parsing the query contains [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|BXXQ0002|#Errors}} the addressed database cannot be opened.<br/>{{Error|FOTY0013|#Errors}} the expression yields function items.

|{{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 />

|Opens Evaluates the XQuery module located at {{Code|$uri}} as file, evaluates it as XQuery expression at runtime, and returns the resulting items. Database nodes in the result A relative URI will be copied and returned insteadresolved against the static base URI of the query.<br />The semantics rules of the {{Code|$bindings}} and {{Code|$options}} parameters is are the same as for [[#xquery:eval|xquery:eval]].

|{{Error|BXXQ0001|#Errors}} the expression contains [[XQuery Update#Updating Expressions|updating expressions]].<br/>{{Error|FOTY0013BXXQ0003|#Errors}} insufficient permissions for evaluating the expression yields function itemsquery.<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.

=Parallelized Execution= 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 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 be optimized by the caching strategies of HD, SSD or operating system. ==xquery:typefork-join==

|{{Func|xquery:typefork-join|$expr functions as itemfunction(*)*|item()*}}|-|'''Summary'''|This function executes the supplied (non-updating) functions in parallel.

| '''SummaryExamples'''|Similar to * The following function sleeps in parallel; it will be finished in 1 second if your system has at least 2 cores:<pre class='brush:xquery'>let $f := function() {{Code|fnprof:sleep(1000) }return xquery:tracefork-join(($exprf, $msgf))}}</pre>* In the following query, but instead of a userup to four URLs will be requested in parallel:<pre class='brush:xquery'>let $funcs := for $segment in 1 to 4 let $url := 'http://url.com/path' || $segment return function() { http:send-defined messagerequest((), it emits the compile$url) }return xquery:fork-join($funcs)</pre>|-time type and estimated result size of its argument|'''Errors'''|{{Error|BXXQ0006|#Errors}} an unexpected error occurred.

|A dynamically evaluated The specified query must not contain contains [[XQuery Update#Updating Expressions|updating expressions]].

|The addressed database cannot be openedspecified query contains no [[XQuery Update#Updating Expressions|updating expressions]].|-|{{Code|BXXQ0003}}|Insufficient permissions for evaluating the query.|-|{{Code|BXXQ0004}}|Query execution exceeded timeout or memory limit.|-|{{Code|BXXQ0005}}|Nested query evaluation is not allowed.|-|{{Code|BXXQ0006}}|An unexpected error occurred.

=Changelog=;Version 8.5* Added: [[#xquery:fork-join|xquery:fork-join]]* 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:parse-uri|xquery:parse-uri]]* Updated: [[#xquery:parse|xquery:parse]]: {{Code|pass}} option added ;Version 8.0* Added: [[#xquery:update|xquery:update]], [[#xquery:parse|xquery:parse]]* Deleted: [[#xquery:evaluate|xquery:evaluate]] (opened databases will now be closed by main query)

* Added: {{Code|$options}} argument added to functions.