Difference between revisions of "Full-Text Module"
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− | This [[Module Library|XQuery Module]] extends the [ | + | This [[Module Library|XQuery Module]] extends the [[Full-Text]] 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|contains text}} expression, can be explicitly requested from items. |
=Conventions= | =Conventions= | ||
Line 5: | Line 5: | ||
All functions and errors in this module are assigned to the <code><nowiki>http://basex.org/modules/ft</nowiki></code> namespace, which is statically bound to the {{Code|ft}} prefix.<br/> | All functions and errors in this module are assigned to the <code><nowiki>http://basex.org/modules/ft</nowiki></code> namespace, which is statically bound to the {{Code|ft}} prefix.<br/> | ||
− | =Functions= | + | =Database Functions= |
==ft:search== | ==ft:search== | ||
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:search( |
− | |- | + | $db as xs:string, |
+ | $terms as item()*, | ||
+ | $options as map(*)? := map { } | ||
+ | ) as text()*</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
|Returns all text nodes from the full-text index of the database {{Code|$db}} that contain the specified {{Code|$terms}}.<br/>The options used for tokenizing the input and building the full-text will also be applied to the search terms. As an example, if the index terms have been stemmed, the search string will be stemmed as well. | |Returns all text nodes from the full-text index of the database {{Code|$db}} that contain the specified {{Code|$terms}}.<br/>The options used for tokenizing the input and building the full-text will also be applied to the search terms. As an example, if the index terms have been stemmed, the search string will be stemmed as well. | ||
The {{Code|$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): | 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}}: | + | * {{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| | + | * {{Code|wildcards}}: turn wildcard querying on or off. Allowed values are {{Code|true}} and {{Code|false}}. By default, wildcard querying is turned off. |
− | * {{Code| | + | * {{Code|fuzzy}}: turn fuzzy querying on or off. Allowed values are {{Code|true}} and {{Code|false}}. By default, fuzzy querying is turned off. |
− | * {{Code|ordered}}: | + | * {{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|content}}: | + | * {{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|scope}}: | + | * {{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|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|unit}}: can be {{Code|sentence}} or {{Code|paragraph}}. It specifies the unit for finding tokens. | ||
− | * {{Code|window}}: | + | * {{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}}: | + | ** {{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|unit}}: can be {{Code|sentences}}, {{Code|sentences}} or {{Code|paragraphs}}. The default is {{Code|words}}. | ||
− | * {{Code|distance}}: | + | * {{Code|distance}}: specify the distance in which tokens must occur. By default, the option is turned off. It has following sub options: |
− | ** {{Code|min}}: | + | ** {{Code|min}}: specify the minimum distance in terms of ''units''. The default is {{Code|0}}. |
− | ** {{Code|max}}: | + | ** {{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}}. | ** {{Code|unit}}: can be {{Code|words}}, {{Code|sentences}} or {{Code|paragraphs}}. The default is {{Code|words}}. | ||
− | |- | + | |- valign="top" |
| '''Errors''' | | '''Errors''' | ||
− | |{{Error|db: | + | |{{Error|db:get|Database Module#Errors}} The addressed database does not exist or could not be opened.<br/>{{Error|db:no-index|Database Module#Errors}} the index is not available.<br/>{{Error|options|#Errors}} the fuzzy and wildcard option cannot be both specified. |
− | |- | + | |- valign="top" |
| '''Examples''' | | '''Examples''' | ||
| | | | ||
Line 41: | Line 46: | ||
* Return all text nodes of the database {{Code|DB}} that contain the numbers {{Code|2010}} and {{Code|2020}}:<br/><code>ft:search("DB", ("2010", "2020"), map { 'mode': 'all' })</code> | * Return all text nodes of the database {{Code|DB}} that contain the numbers {{Code|2010}} and {{Code|2020}}:<br/><code>ft:search("DB", ("2010", "2020"), map { 'mode': 'all' })</code> | ||
* Return text nodes that contain the terms {{Code|A}} and {{Code|B|}} in a distance of at most 5 words: | * Return text nodes that contain the terms {{Code|A}} and {{Code|B|}} in a distance of at most 5 words: | ||
− | < | + | <pre lang='xquery'> |
ft:search("db", ("A", "B"), map { | ft:search("db", ("A", "B"), map { | ||
"mode": "all words", | "mode": "all words", | ||
Line 49: | Line 54: | ||
} | } | ||
}) | }) | ||
− | </ | + | </pre> |
* Iterate over three databases and return all elements containing terms similar to {{Code|Hello World}} in the text nodes: | * Iterate over three databases and return all elements containing terms similar to {{Code|Hello World}} in the text nodes: | ||
− | < | + | <pre lang='xquery'> |
let $terms := "Hello Worlds" | let $terms := "Hello Worlds" | ||
let $fuzzy := true() | let $fuzzy := true() | ||
Line 57: | Line 62: | ||
let $dbname := 'DB' || $db | let $dbname := 'DB' || $db | ||
return ft:search($dbname, $terms, map { 'fuzzy': $fuzzy })/.. | return ft:search($dbname, $terms, map { 'fuzzy': $fuzzy })/.. | ||
− | </ | + | </pre> |
|} | |} | ||
+ | |||
+ | ==ft:tokens== | ||
+ | |||
+ | {| width='100%' | ||
+ | |- valign="top" | ||
+ | | width='120' | '''Signature''' | ||
+ | |<pre>ft:tokens( | ||
+ | $db as xs:string, | ||
+ | $prefix as xs:string := () | ||
+ | ) as element(value)*</pre> | ||
+ | |- valign="top" | ||
+ | | '''Summary''' | ||
+ | |Returns all full-text tokens stored in the index of the database {{Code|$db}}, along with their numbers of occurrences.<br/>If {{Code|$prefix}} is specified, the returned nodes will be refined to the strings starting with that prefix. The prefix will be tokenized according to the full-text used for creating the index. | ||
+ | |- valign="top" | ||
+ | | '''Errors''' | ||
+ | |{{Error|db:get|Database Module#Errors}} The addressed database does not exist or could not be opened.<br/>{{Error|db:no-index|Database Module#Errors}} the full-text index is not available. | ||
+ | |- valign="top" | ||
+ | | '''Examples''' | ||
+ | |Returns the number of occurrences for a single, specific index entry: | ||
+ | <pre lang='xquery'> | ||
+ | let $term := ft:tokenize($term) | ||
+ | return number(ft:tokens('db', $term)[. = $term]/@count) | ||
+ | </pre> | ||
+ | |} | ||
+ | |||
+ | =General Functions= | ||
==ft:contains== | ==ft:contains== | ||
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:contains( |
− | |- | + | $input as item()*, |
+ | $terms as item()*, | ||
+ | $options as map(*)? := map { } | ||
+ | ) as xs:boolean</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | |Checks if the specified {{Code|$input}} items contain the specified {{Code|$terms}}.<br/>The function does the same as the [[Full-Text]] expression {{Code|contains text}}, but options can be specified more dynamically. The {{Code|$options}} are the same as for | + | |Checks if the specified {{Code|$input}} items contain the specified {{Code|$terms}}.<br/>The function does the same as the [[Full-Text]] expression {{Code|contains text}}, but options can be specified more dynamically. The {{Code|$options}} are the same as for {{Function||ft:search}}, and the following ones exist: |
− | * {{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|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|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|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}}. | * {{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''' | | '''Errors''' | ||
|{{Error|options|#Errors}} specified options are conflicting. | |{{Error|options|#Errors}} specified options are conflicting. | ||
− | |- | + | |- valign="top" |
| '''Examples''' | | '''Examples''' | ||
| | | | ||
* Checks if {{Code|jack}} or {{Code|john}} occurs in the input string {{Code|John Doe}}: | * Checks if {{Code|jack}} or {{Code|john}} occurs in the input string {{Code|John Doe}}: | ||
− | < | + | <pre lang='xquery'> |
ft:contains("John Doe", ("jack", "john"), map { "mode": "any" }) | ft:contains("John Doe", ("jack", "john"), map { "mode": "any" }) | ||
− | </ | + | </pre> |
* Calls the function with stemming turned on and off: | * Calls the function with stemming turned on and off: | ||
− | < | + | <pre lang='xquery'> |
(true(), false()) ! ft:contains("Häuser", "Haus", map { 'stemming': ., 'language':'de' }) | (true(), false()) ! ft:contains("Häuser", "Haus", map { 'stemming': ., 'language':'de' }) | ||
− | </ | + | </pre> |
|} | |} | ||
− | ==ft: | + | ==ft:count== |
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:count( |
− | |- | + | $nodes as node()* |
+ | ) as xs:integer</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Returns the number of occurrences of the search terms specified in a full-text expression. |
− | + | |- valign="top" | |
− | |||
− | |- | ||
| '''Examples''' | | '''Examples''' | ||
− | | | + | | |
− | + | * {{Code|ft:count(//*[text() contains text 'QUERY'])}} returns the {{Code|xs:integer}} value {{Code|2}} if a document contains two occurrences of the string "QUERY". | |
− | ft: | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | } | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
|} | |} | ||
− | ==ft: | + | ==ft:score== |
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:score( |
− | |- | + | $item as item()* |
+ | ) as xs:double*</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Returns the score values (0.0 - 1.0) that have been attached to the specified items. {{Code|0}} is returned a value if no score was attached. |
− | |- | + | |- valign="top" |
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * | + | * {{Code|ft:score('a' contains text 'a')}} returns the {{Code|xs:double}} value {{Code|1}}. |
− | |||
− | |||
− | |||
|} | |} | ||
− | ==ft: | + | ==ft:tokenize== |
+ | |||
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:tokenize( |
− | |- | + | $string as xs:string?, |
+ | $options as map(*)? := map { } | ||
+ | ) as xs:string*</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Tokenizes the given {{Code|$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''' | | '''Examples''' | ||
| | | | ||
− | * {{Code|ft: | + | * <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: | + | ==ft:normalize== |
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:normalize( |
− | |- | + | $string as xs:string?, |
+ | $options as map(*)? := map { } | ||
+ | ) as xs:string</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Normalizes the given {{Code|$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''' | | '''Examples''' | ||
| | | | ||
− | * | + | * <code>ft:normalize("Häuser am Meer", map { 'case': 'sensitive' })</code> returns the string {{Code|Hauser am Meer}}. |
|} | |} | ||
− | ==ft: | + | ==ft:thesaurus== |
+ | |||
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:thesaurus( |
− | |- | + | $node as node(), |
+ | $term as xs:string, | ||
+ | $options as map(*)? := map { } | ||
+ | ) as xs:string*</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Looks up a {{Code|$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''' | | '''Examples''' | ||
− | |Returns | + | | 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> | ||
|} | |} | ||
− | ==ft: | + | =Highlighting Functions= |
+ | |||
+ | ==ft:mark== | ||
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:mark( |
− | |- | + | $nodes as node()*, |
+ | $name as xs:string := () | ||
+ | ) as node()*</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Puts a marker element around the resulting {{Code|$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''' | | '''Examples''' | ||
− | | | + | |'''Example 1''': The following query returns {{Code|<XML><mark>hello</mark> world</XML>}}, 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 := 1 | ||
+ | let $end := 10 | ||
+ | let $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><xml>hello <b>word</b></xml></code>: | ||
+ | <pre lang='xquery'> | ||
+ | copy $p := <xml>hello world</xml> | ||
+ | modify () | ||
+ | return ft:mark($p[text() contains text 'word'], 'b') | ||
+ | </pre> | ||
|} | |} | ||
− | ==ft: | + | ==ft:extract== |
{| width='100%' | {| width='100%' | ||
− | |- | + | |- valign="top" |
− | | width='120' | ''' | + | | width='120' | '''Signature''' |
− | | | + | |<pre>ft:extract( |
− | |- | + | $nodes as node()*, |
+ | $name as xs:string := (), | ||
+ | $length as xs:integer := () | ||
+ | ) as node()*</pre> | ||
+ | |- valign="top" | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Extracts and returns relevant parts of full-text results. It puts a marker element around the resulting {{Code|$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''' | | '''Examples''' | ||
| | | | ||
− | * < | + | * The following query may return {{Code|<XML>...<b>hello</b>...<XML>}} if a text node of the database {{Code|DB}} contains the string "hello world": |
+ | <pre lang='xquery'> | ||
+ | ft:extract(db:get('DB')//*[text() contains text 'hello'], 'b', 1) | ||
+ | </pre> | ||
|} | |} | ||
Line 233: | Line 301: | ||
! width="110"|Code | ! width="110"|Code | ||
|Description | |Description | ||
− | |- | + | |- valign="top" |
|{{Code|options}} | |{{Code|options}} | ||
|Both wildcards and fuzzy search have been specified as search options. | |Both wildcards and fuzzy search have been specified as search options. | ||
Line 239: | Line 307: | ||
=Changelog= | =Changelog= | ||
+ | |||
+ | ; Version 9.6 | ||
+ | * Added: {{Function||ft:thesaurus}} | ||
+ | * Updated: {{Function||ft:search}}, {{Function||ft:contains}}: new {{Code|errors}} option. | ||
; Version 9.1 | ; Version 9.1 | ||
− | * Updated: | + | * Updated: {{Function||ft:tokenize}} and {{Function||ft:normalize}} can be called with empty sequence. |
;Version 9.0 | ;Version 9.0 | ||
− | |||
* Updated: error codes updated; errors now use the module namespace | * Updated: error codes updated; errors now use the module namespace | ||
;Version 8.0 | ;Version 8.0 | ||
− | + | * Added: {{Function||ft:contains}}, {{Function||ft:normalize}} | |
− | * Added: | + | * Updated: Options added to {{Function||ft:tokenize}} |
− | * Updated: Options added to | ||
;Version 7.8 | ;Version 7.8 | ||
− | + | * Added: {{Function||ft:contains}} | |
− | * Added: | + | * Updated: Options added to {{Function||ft:search}} |
− | * Updated: Options added to | ||
;Version 7.7 | ;Version 7.7 | ||
− | |||
* Updated: the functions no longer accept [[Database Module#Database Nodes|Database Nodes]] as reference. Instead, the name of a database must now be specified. | * Updated: the functions no longer accept [[Database Module#Database Nodes|Database Nodes]] as reference. Instead, the name of a database must now be specified. | ||
;Version 7.2 | ;Version 7.2 | ||
− | + | * Updated: {{Function||ft:search}} (second argument generalized, third parameter added) | |
− | * Updated: | ||
;Version 7.1 | ;Version 7.1 | ||
− | + | * Added: {{Function||ft:tokens}}, {{Function||ft:tokenize}} | |
− | * Added: |
Latest revision as of 18:34, 1 December 2023
This XQuery Module extends the Full-Text 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 contains text
expression, can be explicitly requested from items.
Contents
Conventions[edit]
All functions and errors in this module are assigned to the http://basex.org/modules/ft
namespace, which is statically bound to the ft
prefix.
Database Functions[edit]
ft:search[edit]
Signature | ft:search( $db as xs:string, $terms as item()*, $options as map(*)? := map { } ) as text()* |
Summary | Returns all text nodes from the full-text index of the database $db that contain the specified $terms .The options used for tokenizing the input and building the full-text will also be applied to the search terms. As an example, if the index terms have been stemmed, the search string will be stemmed as well. The
|
Errors | db:get : The addressed database does not exist or could not be opened.db:no-index : the index is not available.options : the fuzzy and wildcard option cannot be both specified.
|
Examples |
ft:search("db", ("A", "B"), map {
"mode": "all words",
"distance": map {
"max": "5",
"unit": "words"
}
})
let $terms := "Hello Worlds"
let $fuzzy := true()
for $db in 1 to 3
let $dbname := 'DB' || $db
return ft:search($dbname, $terms, map { 'fuzzy': $fuzzy })/..
|
ft:tokens[edit]
Signature | ft:tokens( $db as xs:string, $prefix as xs:string := () ) as element(value)* |
Summary | Returns all full-text tokens stored in the index of the database $db , along with their numbers of occurrences.If $prefix is specified, the returned nodes will be refined to the strings starting with that prefix. The prefix will be tokenized according to the full-text used for creating the index.
|
Errors | db:get : The addressed database does not exist or could not be opened.db:no-index : the full-text index is not available.
|
Examples | Returns the number of occurrences for a single, specific index entry:
let $term := ft:tokenize($term)
return number(ft:tokens('db', $term)[. = $term]/@count)
|
General Functions[edit]
ft:contains[edit]
Signature | ft:contains( $input as item()*, $terms as item()*, $options as map(*)? := map { } ) as xs:boolean |
Summary | Checks if the specified $input items contain the specified $terms .The function does the same as the Full-Text expression contains text , but options can be specified more dynamically. The $options are the same as for ft:search , and the following ones exist:
|
Errors | options : specified options are conflicting.
|
Examples |
ft:contains("John Doe", ("jack", "john"), map { "mode": "any" })
(true(), false()) ! ft:contains("Häuser", "Haus", map { 'stemming': ., 'language':'de' })
|
ft:count[edit]
Signature | ft:count( $nodes as node()* ) as xs:integer |
Summary | Returns the number of occurrences of the search terms specified in a full-text expression. |
Examples |
|
ft:score[edit]
Signature | ft:score( $item as item()* ) as xs:double* |
Summary | Returns the score values (0.0 - 1.0) that have been attached to the specified items. 0 is returned a value if no score was attached.
|
Examples |
|
ft:tokenize[edit]
Signature | ft:tokenize( $string as xs:string?, $options as map(*)? := map { } ) as xs:string* |
Summary | Tokenizes the given $string , using the current default full-text options or the $options specified as second argument, and returns a sequence with the tokenized string. The following options are available:
The |
Examples |
|
ft:normalize[edit]
Signature | ft:normalize( $string as xs:string?, $options as map(*)? := map { } ) as xs:string |
Summary | Normalizes the given $string , using the current default full-text options or the $options specified as second argument. The function accepts the same arguments as ft:tokenize ; special characters and separators will be preserved.
|
Examples |
|
ft:thesaurus[edit]
Signature | ft:thesaurus( $node as node(), $term as xs:string, $options as map(*)? := map { } ) as xs:string* |
Summary | Looks up a $term in a Thesaurus Structure supplied by $node . The following $options exist:
|
Examples | Returns happy and lucky :
ft:thesaurus(
<thesaurus>
<entry>
<term>happy</term>
<synonym>
<term>lucky</term>
<relationship>RT</relationship>
</synonym>
</entry>
</thesaurus>,
'happy'
)
|
Highlighting Functions[edit]
ft:mark[edit]
Signature | ft:mark( $nodes as node()*, $name as xs:string := () ) as node()* |
Summary | Puts a marker element around the resulting $nodes of a full-text request.The default name of the marker element is mark . An alternative name can be chosen via the optional $name argument.Please note that:
|
Examples | Example 1: The following query returns <XML><mark>hello</mark> world</XML> , if one text node of the database DB has the value "hello world":
ft:mark(db:get('DB')//*[text() contains text 'hello'])
Example 2: The following expression loops through the first ten full-text results and marks the results in a second expression: let $start := 1
let $end := 10
let $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(.)])
Example 3: The following expression returns copy $p := <xml>hello world</xml>
modify ()
return ft:mark($p[text() contains text 'word'], 'b')
|
ft:extract[edit]
Signature | ft:extract( $nodes as node()*, $name as xs:string := (), $length as xs:integer := () ) as node()* |
Summary | Extracts and returns relevant parts of full-text results. It puts a marker element around the resulting $nodes of a full-text index request and chops irrelevant sections of the result.The default element name of the marker element is mark . An alternative element name can be chosen via the optional $name argument.The default length of the returned text is 150 characters. An alternative length can be specified via the optional $length argument. Note that the effective text length may differ from the specified text due to formatting and readibility issues.For more details on this function, please have a look at ft:mark .
|
Examples |
ft:extract(db:get('DB')//*[text() contains text 'hello'], 'b', 1)
|
Errors[edit]
Code | Description |
---|---|
options
|
Both wildcards and fuzzy search have been specified as search options. |
Changelog[edit]
- Version 9.6
- Added:
ft:thesaurus
- Updated:
ft:search
,ft:contains
: newerrors
option.
- Version 9.1
- Updated:
ft:tokenize
andft:normalize
can be called with empty sequence.
- Version 9.0
- Updated: error codes updated; errors now use the module namespace
- Version 8.0
- Added:
ft:contains
,ft:normalize
- Updated: Options added to
ft:tokenize
- Version 7.8
- Added:
ft:contains
- Updated: Options added to
ft:search
- Version 7.7
- Updated: the functions no longer accept Database Nodes as reference. Instead, the name of a database must now be specified.
- Version 7.2
- Updated:
ft:search
(second argument generalized, third parameter added)
- Version 7.1
- Added:
ft:tokens
,ft:tokenize