Bureaucrats, editor, reviewer, Administrators
13,550
edits
Changes
Jump to navigation
Jump to search
return order by $s,descending let return $string := 'a bs || 'return ft:score($string contains text 'a' and || $string contains text 'b')n
let for $string n score $s in db:= open('a bfactbook'return ft:score)//text($string )[. contains text 'aorthodox' ftand ]order by $s descendingreturn $s || 'b: ')|| $n
BaseX supports One or more thesaurus files can be specified in a full-text queries using thesauri, but it does not provide a default thesaurusexpression. This is why queries such asThe following query returns {{Code|false}}:
will return If a thesaurus is employed… <syntaxhighlight lang="xml"><thesaurus xmlns="http://www.w3.org/2007/xqftts/thesaurus"> <entry> <term>computers</term> <synonym> <term>hardware</term> <relationship>NT</relationship> <code/synonym>false </codeentry>. However, if the </thesaurus is specified, then the ></syntaxhighlight> …the result will be {{Code|true}}: <codesyntaxhighlight lang="xquery">true'hardware' contains text 'computers' using thesaurus at 'thesaurus.xml'</codesyntaxhighlight> Thesaurus files must comply with the [https://dev.w3.org/2007/xpath-full-text-10-test-suite/TestSuiteStagingArea/TestSources/thesaurus.xsd XSD Schema] of the XQFT Test Suite (but the namespace can be omitted). Apart from the relationship defined in [https://www.iso.org/standard/7776.html ISO 2788] (NT: narrower team, RT: related term, etc.), custom relationships can be used. The type of relationship and the level depth can be specified as well:
The format of the thesaurus files must More details can be the same as the format of the thesauri provided by found in the [https://devwww.w3.org/2007TR/xpath-full-text-10-test-suite XQuery and XPath Full Text 1.0 Test Suite]. It is an XML with structure defined by an [https://dev.w3.org/2007/xpath-full-text-10-test-suite/TestSuiteStagingArea/TestSources/thesaurus.xsd XSD Schema#ftthesaurusoption specification].
Fuzzy search is also supported by the full-<syntaxhighlight lang="xquery">//a[text index.() contains text 'house' using fuzzy 3 errors]</syntaxhighlight>
* Removed: Scoring propagation.
; Version 9.2:
→Thesaurus
<syntaxhighlight lang="xquery">
let $string := 'a b'
return ft:score($string contains text 'a' and $string contains text 'b'),
for $n score $s in db:open('factbook')//religions[text() contains text 'orthodox']
</syntaxhighlight>
Scoring is still supported within full-text expressions , by {{Function|Full-Text|ft:search}}, and by simple predicate tests that can be rewritten to {{Function|Full-Text|ft:search}}:
<syntaxhighlight lang="xquery">
let $string := 'a b'
return ft:score($string contains text 'a' ftand 'b'),
for $n score $s in ft:search('factbook', 'orthodox')
order by $s descendingreturn $s|| ': ' || $n,
</syntaxhighlight>
==Thesaurus==
<syntaxhighlight lang="xquery">
'computershardware' contains text 'hardwarecomputers'
using thesaurus default
</syntaxhighlight>
<syntaxhighlight lang="xquery">
(: BT: find broader terms; NT means narrower term :)
'computers' contains text 'hardware'
using thesaurus at 'XQFTTS_1_0_4/TestSources/usability2x.xml'relationship 'BT' from 1 to 10 levels
</syntaxhighlight>
==Fuzzy Querying==
</syntaxhighlight>
Fuzzy search is based on the Levenshtein distance. The maximum number of allowed errors is calculated by dividing the token length of a specified query term by 4, preserving a minimum of 1 errors. A static error distance can be set by adjusting the {{Option|LSERROR}} option (default: <code>SET LSERROR 0</code>). The query above yields two results as there is no error between the query term “house” and the text node “house”, and one error between “house” and “hous”. A user-defined value can be adjusted globally via the {{Option|LSERROR}} option or, since {{Version|9.6}}, via an additional argument:
=Mixed Content=
=Changelog=
; Version 9.6
* Updated: [[#Fuzzy_Querying|Fuzzy Querying]]: Specify Levenshtein error
; Version 9.5:
* Removed: Scoring propagation.
; Version 9.2:
* Added: Arabic stemmer.
; Version 8.0:
* Updated: [[#Scoring|Scores]] will be propagated by the {{Code|and}} and {{Code|or}} expressions and in predicates.
; Version 7.7:
* Added: [[#Collations|Collations]] support.
; Version 7.3:
* Removed: Trie index, which was specialized on wildcard queries. The fuzzy index now supports both wildcard and fuzzy queries.
* Removed: TF/IDF scoring was discarded in favor of the internal scoring model.
