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Modified Examples Headline
This [[Module Library|XQuery Module]] adds provides additional functions for performing updates and returning results in [[XQuery Update|updating functionsexpressions]].
=Conventions=
All functions in this module are assigned to the <code><nowiki>http://basex.org/modules/update</nowiki></code> namespace, which is statically bound to the {{Code|update}} prefix.<br/>
Except for [[#update:output-cache|update:output-cache]], all functions are ''updating'' and thus comply to the XQuery Update constraints.
=Updates=
==update:apply==
{|
|-
| width='120' | '''Signatures'''
|{{Func|update:apply|$function as function(*), $arguments as array(*))|empty-sequence()}}
|-
| '''Summary'''
|The updating variant of [[XQuery 3.1#fn:apply|fn:apply]] applies the specified updating <code>$function</code> to the specified <code>$arguments</code>.
|-
| '''Examples'''
|
* Creates a new database with an initial document and adds a document to an existing database.
<pre class="brush:xquery">
declare %updating function local:update(
$database as xs:string,
$path as xs:string,
$function as %updating function(item(), xs:string) as empty-sequence()
) as empty-sequence() {
update:apply($function, [ $database, $path ])
};
local:update('new-db', 'doc.xml', db:create#2),
local:update('existing-db', 'doc.xml', db:add#2)
</pre>
|}
==update:for-each==
{|
|-
| width='120' | '''Signatures'''
|{{Func|update:for-each|$seq as item()*, $function as function(item()) as item()*)|empty-sequence()}}
|-
| '''Summary'''
|The updating variant of [[Higher-Order Functions#fn:for-each|fn:for-each]] applies the specified updating <code>$function</code> to every item of <code>$seq</code>.
|-
| '''Examples'''
|
* Creates two databases:
<pre class="brush:xquery">
let $names := ('db1', 'db2')
return update:for-each($names, db:create#1)
</pre>
|}
==update:for-each-pair==
{|
|-
| width='120' | '''Signatures'''
|{{Func|update:for-each-pair|$seq1 as item()*, $function as function(item()) as item()*)|empty-sequence()}}
|-
| '''Summary'''
|The updating variant of [[Higher-Order Functions#fn:for-each-pair|fn:for-each-pair]] applies the specified updating <code>$function</code> to the successive pairs of items of <code>$seq1</code> and <code>$seq2</code>. Evaluation is stopped if one sequence yields no more items.
|-
| '''Examples'''
|
* Renames nodes in an XML snippets:
<pre class="brush:xquery">
copy $xml := <xml><a/><b/></xml>
modify update:for-each-pair(
('a', 'b'),
('d', 'e'),
function($source, $target) {
for $e in $xml/*[name() = $source]
return rename node $e as $target
}
)
return $xml
</pre>
|}
==update:map-for-each==
{| width='100%'
| width='120' | '''Signatures'''
|{{Func|update:map-for-each|$map as map(*), $function as function(xs:anyAtomicType, item()*) as item()*|item()*}}
|-
| '''Summary'''
|The updating variant of {{Function|Map|map:for-each}} applies the specified {{Code|$function}} to every key/value pair of the supplied {{Code|$map}} and returns the results as a sequence.
|-
| '''Examples'''
|
* Inserts attributes into a document:
<pre class="brush:xquery">
copy $doc := <xml/>
modify update:map-for-each(
map {
'id': 'id0',
'value': 456
},
function($key, $value) {
insert node attribute { $key } { $value } into $doc
}
)
return $doc</pre>
|}
=Output=
