Changes

This module [[Module Library|XQuery Module]] extends the [http://www.w3.org/TR/xpath-full[Full-text-10 W3C Full Text Recommendation] with some useful [[Querying#Functions|XQuery functions]]features of BaseX: The index can be directly accessed, full-text results can be marked with additional elements, or the relevant parts can be extracted. Moreover, the score value, which is generated by the <code>{{Code|contains text</code> }} expression, can be explicitly requested from items.  =Conventions= All functions and errors in this module are introduced with assigned to the <code>ft:</code> prefix, which is linked to the <codenowiki>http://www.basex.org/modules/ft</nowiki></code> namespace, which is statically bound to the {{Code|ft}} prefix.<br/> =Database Functions=

 {|width='100%'|-| valign='"top' "| width='90120' | '''SignaturesSignature'''|<code><bpre>ft:search</b>( $node db as nodexs:string, $terms as item()*, $text options as xsmap(*)? :string= map { }) as text()*</codepre>|-| valign='"top' "| '''Summary'''|Performs a Returns all text nodes from the full-text index request on of the specified database node and returns all text nodes {{Code|$db}} that contain the string <code>specified {{Code|$textterms}}.<br/code>. The index options used for tokenizing the input and building the full-text options are used for searching, i.ewill also be applied to the search terms.As an example, if the index terms were have been stemmed, the search string will be stemmed as well.The {{Code|$options}} argument can be used to control full-text processing. The following options are supported (the introduction on [[Full-Text]] processing gives you equivalent expressions in the XQuery Full-Text notation):* {{Code|mode}}: determine the mode how tokens are searched. Allowed values are {{Code|any}}, {{Code|any word}}, {{Code|all}}, {{Code|all words}}, and {{Code|phrase}}. {{Code|any}} is the default search mode.* {{Code|wildcards}}: turn wildcard querying on or off. Allowed values are {{Code|true}} and {{Code|false}}. By default, wildcard querying is turned off.* {{Code|fuzzy}}: turn fuzzy querying on or off. Allowed values are {{Code|true}} and {{Code|false}}. By default, fuzzy querying is turned off.* {{Code|errors}}: control the maximum number of tolerated errors for fuzzy querying. By default, {{Code|0}} is assigned (see [[Full-Text#Fuzzy_Querying|Fuzzy Querying]] for more details).* {{Code|ordered}}: indicate if all tokens must occur in the order in which they are specified. Allowed values are {{Code|true}} and {{Code|false}}. The default is {{Code|false}}.* {{Code|content}}: specify that the matched tokens need to occur at the beginning or end of a searched string, or need to cover the entire string. Allowed values are {{Code|start}}, {{Code|end}}, and {{Code|entire}}. By default, the option is turned off.* {{Code|scope}}: define the scope in which tokens must be located. The option has following sub options:** {{Code|same}}: can be set to {{Code|true}} or {{Code|false}}. It specifies if tokens need to occur in the same or different units.** {{Code|unit}}: can be {{Code|sentence}} or {{Code|paragraph}}. It specifies the unit for finding tokens.* {{Code|window}}: set up a window in which all tokens must be located. By default, the option is turned off. It has following sub options:** {{Code|size}}: specify the size of the window in terms of ''units''.** {{Code|unit}}: can be {{Code|sentences}}, {{Code|sentences}} or {{Code|paragraphs}}. The default is {{Code|words}}.* {{Code|distance}}: specify the distance in which tokens must occur. By default, the option is turned off. It has following sub options:** {{Code|min}}: specify the minimum distance in terms of ''units''. The default is {{Code|0}}.** {{Code|max}}: specify the maximum distance in terms of ''units''. The default is {{Code|∞}}.** {{Code|unit}}: can be {{Code|words}}, {{Code|sentences}} or {{Code|paragraphs}}. The default is {{Code|words}}.| - valign='"top' "| '''Errors'''|{{Error|db:get|Database Module#Errors}} The addressed database does not exist or could not be opened.<bbr/>[[XQuery Errors{{Error|db:no-index|Database Module#BaseX Errors|BASX0002]]}} the index is not available.<br/b> is raised if {{Error|options|#Errors}} the context item does not represent a database nodefuzzy and wildcard option cannot be both specified.|-| valign='"top' "| '''Examples'''

* {{Code|ft:search("DB", "QUERY")}}: Return all text nodes of the database {{Code|DB}} that contain the term {{Code|QUERY}}.* Return all text nodes of the database {{Code|DB}} that contain the numbers {{Code|2010}} and {{Code|2020}}:<br/><code>ft:search(."DB", ("2010", "QUERY2020"), map { 'mode': 'all' })</code> returns all * Return text nodes of the currently opened database that contain the string terms {{Code|A}} and {{Code|B|}} in a distance of at most 5 words:<pre lang='xquery'>ft:search("db", ("A", "B"), map { "mode": "all words", "distance": map { "max": "5", "unit": "words" }})</pre>* Iterate over three databases and return all elements containing terms similar to {{Code|Hello World}} in the text nodes:<pre lang='xquery'>let $terms := "QUERYHello Worlds"let $fuzzy := true()for $db in 1 to 3let $dbname := 'DB' || $dbreturn ft:search($dbname, $terms, map { 'fuzzy': $fuzzy })/..</pre>

==ft:marktokens== {|width='100%'|-| valign='"top' "| width='90120' | '''SignaturesSignature'''|<code><bpre>ft:mark</b>tokens( $nodes db as node()*) as node()*</code><code><b>ftxs:mark</b>($nodes as node()*string, $tag prefix as xs:string := ()) as nodeelement(value)*</codepre>|-| valign='"top' "| '''Summary'''|Puts a marker element around the resulting <code>$nodes</code> of a Returns all full-text tokens stored in the index request.<br />The default tag name of the marker element is <code>mark</code>. An alternative tag name can be chosen via the optional <code>database {{Code|$tag</code> argumentdb}}, along with their numbers of occurrences.<br />Note that If {{Code|$prefix}} is specified, the XML node returned nodes will be refined to be transformed must be an internal "database" nodethe strings starting with that prefix. The <code>transform</code> expression can prefix will be used tokenized according to apply the method to a mainfull-memory fragment (see example)text used for creating the index.|-| valign='"top' "| '''Errors'''|<b>[[XQuery Errors{{Error|db:get|Database Module#BaseX Errors|BASX0002]]</b> is raised if the context item }} The addressed database does not represent a database nodeexist or could not be opened.<br /><b>[[XQuery Errors{{Error|db:no-index|Database Module#Functions Errors|FOCA0002]]</b> }} the full-text index is raised if <code>$name</code> is no valid QNamenot available.|-| valign='"top' "| '''Examples'''|* The following query returns <code>&lt;XML&gt;&lt;mark&gt;hello&lt;/mark&gt; world&lt;/XML&gt;</code>Returns the number of occurrences for a single, if one text node of the database <code>DB</code> has the value "hello world"specific index entry:<pre classlang="brush:'xquery"'>let $term := ft:marktokenize($term)return number(dbft:opentokens('DBdb', $term)//*[text() contains text 'hello'. = $term]/@count)

=General Functions= ==ft:extractcontains== {|width='100%'|-| valign='"top' "| width='90120' | '''SignaturesSignature'''|<code><bpre>ft:extract</b>contains( $nodes input as nodeitem()*) as node()*</code><br /><code><b>ft:extract</b>(, $nodes terms as nodeitem()*, $tag options as xs:string) as nodemap(*)*</code><br /><code><b>ft? :extract</b>($nodes as node(= map { })*, $tag as xs:string, $length as xs:integer) as node()*boolean</codepre>|-| valign='"top' "| '''Summary'''|Extracts and returns relevant parts of full-text results. It puts a marker element around Checks if the resulting <code>specified {{Code|$nodes</code> of a full-text index request and chops irrelevant sections of input}} items contain the resultspecified {{Code|$terms}}.<br />The default tag name of function does the same as the marker element is <code>mark</code>. An alternative tag name [[Full-Text]] expression {{Code|contains text}}, but options can be chosen via specified more dynamically. The {{Code|$options}} are the same as for {{Function||ft:search}}, and the optional <code>$tag</code> argumentfollowing ones exist:* {{Code|case}}: determines how character case is processed. Allowed values are {{Code|insensitive}}, {{Code|sensitive}}, {{Code|upper}} and {{Code|lower}}.<br />The By default length of the returned text , search is <code>150</code> case-insensitive.* {{Code|diacritics}}: determines how diacritical charactersare processed. Allowed values are {{Code|insensitive}} and {{Code|sensitive}}. By default, search is diacritical insensitive. An alternative length can be specified via the optional <code>$length</code> argument* {{Code|stemming}}: determines is tokens are stemmed. Note that the effective text length may differ from the specified text due to formatting Allowed values are {{Code|true}} and readibility issues{{Code|false}}. By default, stemming is turned off.* {{Code|-language}}: determines the language. This option is relevant for stemming tokens. All language codes are supported. The default language is {{Code|en}}.| - valign='"top' "| '''Errors'''|<b>[[XQuery Errors#BaseX Errors{{Error|options|BASX0002]]</b> is raised if the context item does not represent a database node.<br /><b>[[XQuery Errors#Functions Errors|FOCA0002]]</b> is raised if <code>$name</code> is no valid QName}} specified options are conflicting.|-| valign='"top' "| '''Examples'''

* The following query may return <code>&lt;XML&gt;...&lt;b&gt;hello&lt;/b&gt;...&lt;XML&gt;</code> Checks if a text node of {{Code|jack}} or {{Code|john}} occurs in the database input string {{Code|John Doe}}:<codepre lang='xquery'>DBft:contains("John Doe", ("jack", "john"), map { "mode": "any" })</codepre> contains * Calls the string "hello world"function with stemming turned on and off:<pre classlang="brush:'xquery"'>ft:extract(db:opentrue('DB')//*[text, false() ) ! ft:contains text ("Häuser", "Haus", map { 'hellostemming']: ., 'blanguage', 1:'de' })

 {|width='100%'|-| valign='"top' "| width='90120' | '''SignaturesSignature'''|<code><bpre>ft:count</b>( $nodes as node()*) as xs:integer</codepre>|-| valign='"top' "| '''Summary'''

|-| valign='"top' | '''Errors'''|<b>[[XQuery Errors#BaseX Errors|BASX0002]]</b> is raised if one of the resulting items is not a database node.|-"| valign='top' | '''Examples'''

* <code>{{Code|ft:count(//*[text() contains text 'QUERY'])</code> }} returns the <code>{{Code|xs:integer</code> }} value <code>{{Code|2</code> }} if a document contains two occurrences of the string "QUERY".

 {|width='100%'|-| valign='"top' "| width='90120' | '''SignaturesSignature'''|<code><bpre>ft:score</b>( $item as item()*) as xs:double*</codepre>|-| valign='"top' "| '''Summary'''|Returns the score values (0.0 - 1.0) that have been attached to the specified items. <code>{{Code|0</code> }} is returned a value if no score was attached.|-valign="top"| '''Examples'''|* {{Code|ft:score('a' contains text 'a')}} returns the {{Code|xs:double}} value {{Code|1}}.|} ==ft:tokenize== {| width='100%'|- valign="top"| width='120' | '''Signature'''|<pre>ft:tokenize( $string as xs:string?, $options as map(*)? := map { }) as xs:string*</pre>|- valign="top"| '''Summary'''|Tokenizes the given {{Code|$string}}, using the current default full-text options or the {{Code|$options}} specified as second argument, and returns a sequence with the tokenized string. The following options are available:* {{Code|case}}: determines how character case is processed. Allowed values are {{Code|insensitive}}, {{Code|sensitive}}, {{Code|upper}} and {{Code|lower}}. By default, search is case insensitive.* {{Code|diacritics}}: determines how diacritical characters are processed. Allowed values are {{Code|insensitive}} and {{Code|sensitive}}. By default, search is diacritical insensitive.* {{Code|stemming}}: determines is tokens are stemmed. Allowed values are {{Code|true}} and {{Code|false}}. By default, stemming is turned off.* {{Code|language}}: determines the language. This option is relevant for stemming tokens. All language codes are supported. The default language is {{Code|en}}.The {{Code|$options}} argument can be used to control full-text processing.|- valign="top"| '''Examples'''|* <code>ft:tokenize("No Doubt")</code> returns the two strings {{Code|no}} and {{Code|doubt}}.* <code>ft:tokenize("École", map { 'diacritics': 'sensitive' })</code> returns the string {{Code|école}}.* <code>declare ft-option using stemming; ft:tokenize("GIFTS")</code> returns a single string {{Code|gift}}.|} ==ft:normalize== {| width='100%'|- valign="top"| width='120' | '''Signature'''|<pre>ft:normalize( $string as xs:string?, $options as map(*)? := map { }) as xs:string</pre>|- valign="top"| '''Summary'''|Normalizes the given {{Code|$string}}, using the current default full-text options or the {{Code|$options}} specified as second argument. The function accepts the same arguments as {{Function||ft:tokenize}}; special characters and separators will be preserved.|- valign="top"| '''Examples'''| * <code>ft:normalize("Häuser am Meer", map { 'case': 'sensitive' })</code> returns the string {{Code|Hauser am Meer}}.|} ==ft:thesaurus== {| width='100%'|- valign="top"| width='120' | '''Signature'''|<pre>ft:thesaurus( $node as node(), $term as xs:string, $options as map(*)? := map { }) as xs:string*</pre>|- valign="top"| ' ''Summary'''|Looks up a {{Code|$term}} in a [[Full-Text#Thesaurus|Thesaurus Structure]] supplied by {{Code|$node}}. The following {{Code|$options}} exist:* {{Code|relationship}}: determines the relationship between terms* {{Code|levels}}: determines the maximum number of levels to traverse|- valign="top"| '''Examples'''| Returns {{Code|happy}} and {{Code|lucky}}:<pre lang='xquery'>ft:thesaurus( <thesaurus> <entry> <term>happy</term> <synonym> <term>lucky</term> <relationship>RT</relationship> </synonym> </entry> </thesaurus>, 'happy')</pre>|} =Highlighting Functions= ==ft:mark== {| width='100%'|- valign="top"| width='120' | '''Signature'''|<pre>ft:mark( $nodes as node()*, $name as xs:string := ()) as node()*</pre>|- valign="top"| '''Summary'''|Puts a marker element around the resulting {{Code|$nodes}} of a full-text request.<br/>The default name of the marker element is {{Code|mark}}. An alternative name can be chosen via the optional {{Code|$name}} argument.<br/>Please note that:* The full-text expression that computes the token positions must be specified as argument of the <code>ft:mark()</code> function, as all position information is lost in subsequent processing steps. You may need to specify more than one full-text expression if you want to use the function in a FLWOR expression, as shown in Example 2.* The supplied node must be a [[Database Module#Database Node|Database Node]]. As shown in Example 3, {{Code|update}} or {{Code|transform}} can be utilized to convert a fragment to the required internal representation.|- valign="top"| '''Examples'''|'''Example 1''': The following query returns {{Code|&lt;XML&gt;&lt;mark&gt;hello&lt;/mark&gt; world&lt;/XML&gt;}}, if one text node of the database {{Code|DB}} has the value "hello world":<pre lang='xquery'>ft:mark(db:get('DB')//*[text() contains text 'hello'])</pre>'''Example 2''': The following expression loops through the first ten full-text results and marks the results in a second expression:<pre lang='xquery'>let $start := 1let $end := 10let $term := 'welcome'let $test := function($node) { $node/text() contains text { $term } }for $ft in (db:get('DB')//*[$test(.)])[position() = $start to $end]return ft:mark($ft[$test(.)])</pre>'''Example 3''': The following expression returns <code>&lt;xml>hello &lt;b&gt;word&lt;/b&gt;&lt;/xml&gt;</code>:<pre lang='xquery'>copy $p := <xml>hello world</xml>modify ()return ft:mark($p[text() contains text 'word'], 'b')</pre>|} ==ft:extract== {| width='100%'|- valign="top"| width='120' | '''Signature'''|<pre>ft:extract( $nodes as node()*, $name as xs:string := (), $length as xs:integer := ()) as node()*</pre>|- valign="top"| '''Summary'''|Extracts and returns relevant parts of full-text results. It puts a marker element around the resulting {{Code|$nodes}} of a full-text index request and chops irrelevant sections of the result.<br/>The default element name of the marker element is {{Code|mark}}. An alternative element name can be chosen via the optional {{Code|$name}} argument.<br/>The default length of the returned text is {{Code|150}} characters. An alternative length can be specified via the optional {{Code|$length}} argument. Note that the effective text length may differ from the specified text due to formatting and readibility issues.<br/>For more details on this function, please have a look at {{Function||ft:mark}}.|- valign="top"| '''Examples'''

* The following query may return {{Code|&lt;XML&gt;...&lt;b&gt;hello&lt;/b&gt;...&lt;XML&gt;}} if a text node of the database {{Code|DB}} contains the string "hello world":<codepre lang='xquery'>ft:scoreextract(db:get('aDB' )//*[text() contains text 'ahello'], 'b', 1)</codepre> returns the <code>xs:double</code> value <code>1</code>.

=Errors= {| class="wikitable" width="100%"! width="110"|Code|Description|- valign="top"|{{Code|options}}|Both wildcards and fuzzy search have been specified as search options.|} =Changelog= ; Version 9.6* Added: {{Function||ft:thesaurus}}* Updated: {{Function||ft:search}}, {{Function||ft:contains}}: new {{Code|errors}} option. ; Version 9.1* Updated: {{Function||ft:tokenize}} and {{Function||ft:normalize}} can be called with empty sequence. ;Version 9.0* Updated: error codes updated; errors now use the module namespace ;Version 8.0* Added: {{Function||ft:contains}}, {{Function||ft:normalize}}* Updated: Options added to {{Function||ft:tokenize}} ;Version 7.8* Added: {{Function||ft:contains}}* Updated: Options added to {{Function||ft:search}} ;Version 7.7* Updated: the functions no longer accept [[Category:XQueryDatabase Module#Database Nodes|Database Nodes]]as reference. Instead, the name of a database must now be specified. ;Version 7.2* Updated: {{Function||ft:search}} (second argument generalized, third parameter added) ;Version 7.1* Added: {{Function||ft:tokens}}, {{Function||ft:tokenize}}